Ukuphuhliswa kokusebenza okuphezulu, i-sensors yegesi ephathekayo kunye ne-miniaturized ifumana ingqwalasela eyandayo kwiinkalo zokubeka iliso lokusingqongileyo, ukhuseleko, ukuxilongwa kwezonyango kunye nezolimo.Phakathi kwezixhobo ezahlukeneyo zokufumanisa, i-metal-oxide-semiconductor (MOS) i-chemo-resistive gas sensors yinkqubo ethandwa kakhulu kwizicelo zorhwebo ngenxa yokuzinza kwazo okuphezulu, ixabiso eliphantsi, kunye novakalelo oluphezulu.Enye yezona ndlela zibalulekileyo zokuphucula ngakumbi ukusebenza kwenzwa kukudalwa kwe-nanosized MOS-based heterojunctions (i-hetero-nanostructured MOS) esuka kwi-MOS nanomaterials.Nangona kunjalo, indlela yokuva ye-heteronanostructured MOS sensor yahlukile kuleyo ye-MOS yenzwa yegesi enye, njengoko intsonkothile kakhulu.Ukusebenza kwenzwa kuchatshazelwa ziiparamitha ezahlukeneyo, kubandakanywa ubume bomzimba kunye neekhemikhali zemathiriyeli enovakalelo (efana nobungakanani beenkozo, ingxinano yesiphene, kunye nezithuba zemathiriyeli zeoksijini), ubushushu bokusebenza, kunye nolwakhiwo lwesixhobo.Olu phononongo lubonisa iikhonsepthi ezininzi zokuyila izinzwa zegesi ezisebenza kakhulu ngokuhlalutya indlela yokuva ye-nanostructured MOS sensors.Ukongezelela, impembelelo yesakhiwo sejometri yesixhobo, esinqunywe ngobudlelwane phakathi kwezinto ezithintekayo kunye ne-electrode esebenzayo, kuxoxwa ngayo.Ukufunda ukuziphatha kwenzwa ngokucwangcisiweyo, eli nqaku lazisa kwaye lixoxe ngendlela eqhelekileyo yombono wezakhiwo ezintathu zejometri eziqhelekileyo zezixhobo ezisekelwe kwizinto ezahlukeneyo ze-heteronanostructured.Olu qwalaselo luya kusebenza njengesikhokelo kubafundi bexesha elizayo abafunda iindlela ezinovakalelo zezivamvo zerhasi kwaye baphuhlise abenzi boluvo begesi ephezulu.
Ungcoliseko lomoya yingxaki eyandayo kwaye yingxaki enkulu yehlabathi jikelele esongela impilo-ntle yabantu kunye nezidalwa eziphilayo.Ukuphefumla izinto ezingcolisa igesi kunokubangela iingxaki ezininzi zempilo ezifana nesifo sokuphefumla, umhlaza wemiphunga, i-leukemia kunye nokufa kwangaphambi kwexesha1,2,3,4.Ukusukela ngo-2012 ukuya ku-2016, izigidi zabantu kuxelwe ukuba zibhubhile ngenxa yongcoliseko lomoya, kwaye nyaka ngamnye, iibhiliyoni zabantu ziye zachanabeka kumgangatho ophantsi womoya5.Ngoko ke, kubalulekile ukuphuhlisa i-sensors yegesi ephathekayo kunye ne-miniaturized enokubonelela ngengxelo yexesha langempela kunye nokusebenza okuphezulu kokufumanisa (umzekelo, uvakalelo, ukukhetha, ukuzinza, kunye nokuphendula kunye namaxesha okubuyisela).Ukongeza kokubeka iliso kokusingqongileyo, izinzwa zegesi zidlala indima ebalulekileyo kukhuseleko6,7,8, ukuxilongwa kwezonyango9,10, i-aquaculture11 kunye nezinye iindawo12.
Ukuza kuthi ga ngoku, iisensonsi zegesi ezininzi eziphathekayo ezisekelwe kwiindlela ezahlukeneyo zokuva ziye zaziswa, ezifana ne-optical13,14,15,16,17,18, electrochemical19,20,21,22 kunye ne-chemical resistive sensors23,24.Phakathi kwazo, i-metal-oxide-semiconductor (MOS) i-chemical resistive sensors yizona zithandwa kakhulu kwizicelo zorhwebo ngenxa yokuzinza kwazo okuphezulu kunye neendleko eziphantsi25,26.Ingqwalasela engcolileyo inokumiselwa ngokulula ngokufumanisa utshintsho kwi-MOS ukumelana.Kwiminyaka yokuqala ye-1960, i-chemo-resistive gas sensors yokuqala esekelwe kwiifilimu ezincinci ze-ZnO zabikwa, zivelisa umdla omkhulu kwintsimi yokufumanisa igesi27,28.Namhlanje, iiMOS ezininzi ezahlukeneyo zisetyenziswa njengezinto ezibuthathaka zegesi, kwaye zinokwahlulwa zibe ngamacandelo amabini ngokusekwe kwiimpawu zazo zomzimba: i-n-uhlobo lwe-MOS enee-electron njengoyena mthwalo wokuthwala kunye ne-p-uhlobo lwe-MOS enemingxuma njengoko uninzi lwabathwali bentlawulo.ukuhlawulisa abathwali.Ngokubanzi, i-p-type MOS ayithandwa kakhulu kune-n-type MOS ngenxa yokuba impendulo ye-inductive yohlobo lwe-p-MOS (Sp) ilingana nengcambu ye-n-uhlobo lwe-MOS (\(S_p = \ sqrt { S_n}\ ) ) kwiingcamango ezifanayo (umzekelo, isakhiwo esifanayo se-morphological kunye noshintsho olufanayo lokugoba kweebhendi emoyeni) 29,30.Nangona kunjalo, izinzwa ze-MOS ezisisiseko esinye zisajongene neengxaki ezifana nokungonelanga komda wokubona, uvakalelo oluphantsi kunye nokukhetha kwizicelo ezisebenzayo.Imiba yokukhetha ingaqwalaselwa kwinqanaba elithile ngokudala i-arrays of sensors (ebizwa ngokuthi "iimpumlo ze-elektroniki") kunye nokubandakanya i-algorithms yohlalutyo lwe-computational ezifana noqeqesho lwe-vector quantization (LVQ), uhlalutyo lwecandelo eliphambili (PCA), kunye nohlalutyo lwe-square encinci (PLS)31, 32, 33, 34, 35. Ukongeza, ukuveliswa kwe-low-dimensional MOS32,36,37,38,39 (umz. i-one-dimensional (1D), i-0D kunye ne-2D nanomaterials), kunye nokusetyenziswa kwamanye ama-nanomaterials ( umz. i-MOS40,41,42, i-noble metal nanoparticles (NPs))43,44, carbon nanomaterials45,46 kunye ne-conductive polymers47,48) ukudala i-nanoscale heterojunctions (okt, i-heteronanostructured MOS) zezinye iindlela ezikhethiweyo zokusombulula ezi ngxaki zingentla.Xa kuthelekiswa neefilimu ze-MOS ezityebileyo zemveli, i-MOS enomgangatho ophantsi enendawo ethile ephezulu inokubonelela ngeendawo ezisebenzayo zokubhengeza igesi kwaye iququzelele ukusasazwa kwerhasi36,37,49.Ukongezelela, ukuyila kwe-MOS-based heteronanostructures kunokuqhubela phambili ukuthuthwa kwezithuthi ze-carrier kwi-heterointerface, okubangelwa utshintsho olukhulu ekuchaseni ngenxa yemisebenzi eyahlukeneyo yokusebenza50,51,52.Ukongezelela, ezinye zeempembelelo zemichiza (umzekelo, umsebenzi we-catalytic kunye ne-synergistic surface reactions) eyenzeka kwi-design ye-MOS heteronanostructures inokuphucula ukusebenza kwenzwa.50,53,54 Nangona ukuyila kunye nokwenza i-MOS heteronanostructures iya kuba yindlela ethembisayo yokuphucula. ukusebenza kwesivamvo, izinzwa zale mihla ze-chemo-resistive zisebenzisa uvavanyo kunye neempazamo, ezidla ixesha kwaye zingasebenzi kakuhle.Ke ngoko, kubalulekile ukuqonda indlela yokuva ye-MOS esekwe kwi-sensors yegesi njengoko inokukhokela uyilo lwezinzwa eziphezulu zendlela yokusebenza.
Kwiminyaka yakutshanje, ii-sensors zegesi ze-MOS ziye zaphuhliswa ngokukhawuleza kwaye ezinye iingxelo zipapashwe kwi-MOS nanostructures55,56,57, i-sensors yegesi yeqondo lokushisa kwegumbi58,59, izixhobo ezikhethekileyo ze-MOS sensor60,61,62 kunye ne-specialty gas sensors63.Iphepha lokuphonononga kwezinye iiPhononongo lijolise ekucaciseni indlela yokuva i-gas sensors esekelwe kwi-intrinsic physical and chemical properties of MOS, kubandakanywa nendima yezithuba ze-oksijini 64, indima ye-heteronanostructures 55, 65 kunye nokudluliselwa kwentlawulo kwi-heterointerfaces 66. Ukongezelela , ezinye iiparamitha ezininzi zichaphazela ukusebenza kwenzwa, kubandakanywa i-heterostructure, ubukhulu bengqolowa, ubushushu bokusebenza, ubuninzi be-defect, izithuba ze-oksijini, kunye neenqwelo zekristali ezivulekileyo zezinto ezibuthathaka25,67,68,69,70,71.72, 73. Nangona kunjalo, i-geometric structure yesixhobo (esingaqhelekanga), esinqunywe ngubudlelwane phakathi kwezinto zokuva kunye ne-electrode esebenzayo, nayo ichaphazela kakhulu uvakalelo lwe-sensor74,75,76 (jonga icandelo lesi-3 ngolwazi olungakumbi) .Ngokomzekelo, uKumar et al.I-77 ichaze i-gas sensors ezimbini ezisekelwe kwizinto ezifanayo (umzekelo, izinzwa zegesi ezinamaleko amabini ezisekwe kwi-TiO2@NiO kunye ne-NiO@TiO2) kwaye yabona utshintsho olwahlukileyo kwi-NH3 yokuxhathisa igesi ngenxa yejometri yesixhobo esahlukileyo.Ngoko ke, xa uhlalutya indlela yokubona igesi, kubalulekile ukuqwalasela isakhiwo sesixhobo.Kolu hlaziyo, ababhali bagxininise kwiindlela zokukhangela ezisekwe kwi-MOS kwiintlobo ezahlukeneyo ze-nanostructures kunye nezakhiwo zesixhobo.Sikholelwa ukuba olu hlaziyo lunokusebenza njengesikhokelo kubafundi abanqwenela ukuqonda kunye nokuhlalutya iindlela zokubona igesi kwaye banokuba negalelo ekuphuhliseni i-sensors yegesi ephezulu yexesha elizayo.
Kwikhiwane.I-1a ibonisa imodeli esisiseko yendlela yokuva igesi esekelwe kwi-MOS enye.Njengoko iqondo lokushisa liphakama, i-adsorption ye-oksijini (i-O2) iamolekyu kwindawo ye-MOS iya kutsala ii-electron ezivela kwi-MOS kwaye zenze iintlobo ze-anionic (ezifana ne-O2- kunye ne-O-).Emva koko, i-electron depletion layer (EDL) ye-n-type MOS okanye i-hole accumulation layer (HAL) ye-p-type MOS iye yenziwa kumphezulu we-MOS 15, 23, 78. Ukusebenzisana phakathi kwe-O2 kunye I-MOS ibangela ukuba ibhendi yokuqhuba yobuso be-MOS igobe phezulu kwaye yenze umqobo onokubakho.Emva koko, xa i-sensor ibonakaliswe kwi-gas ekujoliswe kuyo, i-gas adsorbed phezu kwendawo ye-MOS isabela kunye neentlobo ze-ionic oxygen, mhlawumbi zitsala ii-electron (i-oxidizing gas) okanye i-electron yokunikela (igesi yokunciphisa).Ukutshintshwa kwe-electron phakathi kwegesi ekujoliswe kuyo kunye ne-MOS inokulungelelanisa ububanzi be-EDL okanye i-HAL30,81 ebangela ukuba utshintsho kwi-resistance jikelele ye-MOS sensor.Ngokomzekelo, i-gesi yokunciphisa, ii-electron ziya kudluliselwa kwi-gas yokunciphisa ukuya kwi-n-type MOS, okubangelwa i-EDL ephantsi kunye nokuchasana okuphantsi, okubizwa ngokuba yi-n-type sensor behavior.Ngokwahlukileyo, xa i-p-type MOS ibonakaliswe kwigesi yokunciphisa emisela ukuziphatha kobuntu be-p, i-HAL iyancipha kwaye ukuchasana kuyanda ngenxa yomnikelo we-electron.Kwiigesi ze-oxidizing, impendulo yenzwa ichasene naleyo yokunciphisa iigesi.
Iindlela ezisisiseko zokubona uhlobo lwe-n kunye ne-p-uhlobo lwe-MOS yokunciphisa kunye neegesi ze-oxidizing b Izinto eziphambili kunye ne-physico-chemical okanye izinto eziphathekayo ezibandakanyekayo kwi-semiconductor gas sensors 89
Ngaphandle kwendlela yokufumanisa isiseko, iindlela zokubona irhasi ezisetyenziswa kwizivamvo zerhasi ezisebenzayo zintsokothile.Ngokomzekelo, ukusetyenziswa kwangempela kwenzwa yegesi kufuneka kuhlangabezane neemfuno ezininzi (ezifana novelwano, ukukhetha, kunye nokuzinza) kuxhomekeke kwiimfuno zomsebenzisi.Ezi mfuno zihambelana ngokusondeleyo neempawu ezibonakalayo kunye neekhemikhali zezinto ezibuthathaka.Umzekelo, u-Xu et al.71 ubonise ukuba i-SnO2 esekelwe kwi-sensor ifezekisa uvakalelo oluphezulu xa i-crystal diameter (d) ilingana okanye ingaphantsi kabini ubude be-Debye (λD) ye-SnO271.Xa i-d ≤ 2λD, i-SnO2 iphelile ngokupheleleyo emva kokubhengezwa kwee-molecule ze-O2, kwaye impendulo yenzwa kwi-gas yokunciphisa iphezulu.Ukongeza, ezinye iiparamitha ezahlukeneyo zinokuchaphazela ukusebenza kwenzwa, kubandakanya ubushushu bokusebenza, iziphene zekristale, kunye neenqwelomoya zekristale eziveziweyo zezinto zokuva.Ngokukodwa, impembelelo yokushisa okusebenzayo ichazwa ngokhuphiswano olunokwenzeka phakathi kweereyithi ze-adsorption kunye ne-desorption ye-target target, kunye ne-reactivity surface phakathi kwe-adsorbed gas molecules kunye ne-oksijini particles4,82.Isiphumo seziphene zekristale zihambelana kakhulu nomxholo wezithuba ze-oxygen [83, 84].Ukusebenza kwenzwa kunokuchaphazeleka kwakhona kwi-reactivity eyahlukeneyo ye-crystal faces evulekileyo67,85,86,87.Iinqwelomoya ezivulekileyo zekristale ezinoxinano olusezantsi ziveza iications zentsimbi ezingalungelelanisiweyo ezinamandla aphezulu, ezikhuthaza ukubhengezwa komphezulu kunye nokusebenza kwakhona88.Itheyibhile yoku-1 idwelisa izinto ezininzi eziphambili kunye neendlela zokuqonda eziphuculweyo ezinxulumene nazo.Ngoko ke, ngokulungelelanisa ezi parameters eziphathekayo, ukusebenza kokufumanisa kunokuphuculwa, kwaye kubalulekile ukugqiba izinto eziphambili ezichaphazela ukusebenza kwenzwa.
I-Yamazoe89 kunye no-Shimanoe et al.68,71 benze inani lezifundo kwi-theoretical mechanism ye-sensor perception kwaye bacebise izinto ezintathu ezizimeleyo ezichaphazela ukusebenza kwenzwa, ngokukodwa umsebenzi we-receptor, umsebenzi we-transducer, kunye ne-utility (Fig. 1b)..Umsebenzi we-receptor ubhekiselele kwisakhono somphezulu we-MOS ukusebenzisana neemolekyuli zegesi.Lo msebenzi unxulumene ngokusondeleyo neepropati zeekhemikhali ze-MOS kwaye unokuphuculwa kakhulu ngokuzisa abamkeli bangaphandle (umzekelo, ii-NP zensimbi kunye nezinye i-MOS).Umsebenzi we-transducer ubhekiselele ekukwazini ukuguqula ukusabela phakathi kwegesi kunye ne-MOS surface ibe ngumqondiso wombane olawulwa yimida yengqolowa ye-MOS.Ngaloo ndlela, umsebenzi we-sensory uchaphazeleka kakhulu yi-MOC ubungakanani be-particle kunye noxinaniso lwama-receptors angaphandle.U-Katoch et al.90 wabika ukuba ubungakanani bengqolowa yokunciphisa i-ZnO-SnO2 nanofibrils ibangele ukubunjwa kwee-heterojunctions ezininzi kunye nokwanda kwe-sensor sensor, ehambelana nokusebenza kwe-transducer.U-Wang et al.91 uqhathanise ubungakanani beengqolowa ezahlukeneyo ze-Zn2GeO4 kwaye wabonisa ukunyuka kwe-6.5-fold in sensor sensitivity emva kokuzisa imida yeenkozo.I-Utility yenye into ebalulekileyo yokusebenza kwenzwa echaza ukufumaneka kwegesi kwisakhiwo sangaphakathi seMOS.Ukuba iimolekyuli zegesi azikwazi ukungena kwaye ziphendule kunye ne-MOS yangaphakathi, ukuvakalelwa kwenzwa kuya kuncitshiswa.Uncedo lunxulumene ngokusondeleyo nobunzulu bokusasazwa kwerhasi ethile, exhomekeke kubungakanani bepore besixhobo sokuva.U-Sakai et al.I-92 ibonise uvakalelo lwe-sensor kwiigesi ze-flue kwaye yafumanisa ukuba zombini ubunzima be-molecular of the gas kunye ne-pore radius ye-membrane ye-sensor ichaphazela uvakalelo lwe-sensor kwi-gas diffusion deep in the membrane sensor.Ingxoxo engasentla ibonisa ukuba i-sensors zegesi ephezulu zinokuthi ziphuhliswe ngokulinganisa kunye nokuphucula umsebenzi we-receptor, umsebenzi we-transducer, kunye nokusetyenziswa.
Lo msebenzi ungasentla ucacisa indlela yokuqonda esisiseko ye-MOS enye kwaye ixoxa ngezinto ezininzi ezichaphazela ukusebenza kweMOS.Ukongeza kwezi zinto, izinzwa zegesi ezisekelwe kwi-heterostructures zinokuphucula ngakumbi ukusebenza kwenzwa ngokuphucula kakhulu inzwa kunye nemisebenzi ye-receptor.Ukongeza, i-heteronanostructures inokuphucula ngakumbi ukusebenza kwenzwa ngokunyusa ukuphendulwa kwe-catalytic, ukulawula ukuhanjiswa kwentlawulo, kunye nokudala iindawo ezininzi ze-adsorption.Ukuza kuthi ga ngoku, uninzi lwezinzwa zegesi ezisekelwe kwi-MOS heteronanostructures ziye zaphononongwa ukuxoxa ngeendlela zokuphucula i-sensor95,96,97.Miller et al.I-55 ishwankathele iindlela ezininzi ezinokuthi ziphucule uvakalelo lwe-heteronanostructures, kubandakanywa ukuxhomekeka-kumphezulu, ukuxhomekeka-ukuxhomekeka, kunye nolwakhiwo-luxhomekeke.Phakathi kwazo, indlela yokukhulisa i-interface-exhomekeke kwi-interface intsonkothe kakhulu ukugubungela lonke unxibelelwano lwe-interface kwithiyori enye, kuba ii-sensor ezahlukeneyo ezisekwe kwizinto ezenziwe nge-heteronanostructured (umzekelo, i-nn-heterojunction, i-pn-heterojunction, i-pp-heterojunction, njl.njl.) .Schottky knot).Ngokuqhelekileyo, i-MOS-based sensors heteronanostructured sensors isoloko ibandakanya ezimbini okanye ngaphezulu kweendlela eziphambili ze-sensor98,99,100.Impembelelo ye-synergistic yezi ndlela zokwandisa inokunyusa ukwamkelwa kunye nokulungiswa kwemiqondiso yenzwa.Ke, ukuqonda indlela yokuqonda i-sensor esekwe kwi-heterogeneous nanostructured materials ibalulekile ukuze kuncedwe abaphandi baphuhlise i-bottom-up sensors zegesi ngokuhambelana neemfuno zabo.Ukongezelela, isakhiwo sejometri yesixhobo sinokuchaphazela kakhulu uvakalelo lwe-sensor 74, 75, 76. Ukuze uhlalutye ngokuchanekileyo ukuziphatha kwenzwa, iindlela zokuvalelwa kwezixhobo ezintathu ezisekelwe kwizinto ezahlukeneyo ze-heteronanostructured ziya kuboniswa. kwaye kuxoxwe ngezantsi.
Ngophuhliso olukhawulezayo lwee-sensors zegesi ezisekelwe kwi-MOS, i-MOS eyahlukeneyo ye-hetero-nanostructured iye yacetywayo.Ukudluliselwa kwentlawulo kwi-heterointerface kuxhomekeke kumanqanaba ahlukeneyo eFermi (Ef) yamacandelo.Kwi-heterointerface, ii-electron zihamba ukusuka kwelinye icala kunye ne-Ef enkulu ukuya kwelinye icala kunye ne-Ef encinci de amanqanaba abo e-Fermi afikelele kwi-equilibrium, kunye nemingxuma, ngokuchaseneyo.Emva koko abathwali kwi-heterointerface baphelile kwaye benze uluhlu oluncitshisiweyo.Emva kokuba i-sensor ibonakaliswe kwi-gas ekujoliswe kuyo, i-heteronanostructured i-mos ye-concentration carrier iyatshintsha, njengoko kwenza ukuphakama komqobo, ngaloo ndlela iphucula isignali yokufumanisa.Ukongeza, iindlela ezahlukeneyo zokwenza i-heteronanostructures zikhokelela kubudlelwane obahlukeneyo phakathi kwemathiriyeli kunye nee-electrode, ezikhokelela kwiijometri zesixhobo ezahlukeneyo kunye neendlela ezahlukeneyo zokuvamvo.Kolu hlaziyo, siphakamisa izakhiwo ezintathu zezixhobo zejometri kwaye sixoxe ngendlela yokuva kwisakhiwo ngasinye.
Nangona i-heterojunctions idlala indima ebaluleke kakhulu ekusebenzeni kokukhangela igesi, i-geometry yesixhobo se-sensor yonke inokuchaphazela kakhulu indlela yokuziphatha yokufumanisa, ekubeni indawo yomzila we-sensor conduction ixhomekeke kakhulu kwijometri yesixhobo.Iijometri ezintathu eziqhelekileyo zezixhobo ze-MOS ze-heterojunction zixoxwa apha, njengoko kubonisiwe kwi-Figure 2. Kuhlobo lokuqala, uqhagamshelwano lwe-MOS ezimbini lusasazwa ngokungacwangciswanga phakathi kwee-electrode ezimbini, kwaye indawo yomjelo wokuqhuba imiselwa yi-MOS ephambili, eyesibini yileyo. ukubunjwa kwee-nanostructures ezingafaniyo ezivela kwi-MOS eyahlukileyo, ngelixa i-MOS enye kuphela iqhagamshelwe kwi-electrode.I-electrode ixhunyiwe, ngoko i-channel conductive idla ngokuhlala ngaphakathi kwe-MOS kwaye ixhunywe ngokuthe ngqo kwi-electrode.Kuhlobo lwesithathu, izinto ezimbini zifakwe kwi-electrodes ezimbini ngokwahlukileyo, zikhokela isixhobo nge-heterojunction eyenziwe phakathi kwezinto ezimbini.
Iqhagamshela phakathi kweekhompawundi (umz. “SnO2-NiO”) ibonisa ukuba la malungu mabini axubene nje (uhlobo I).Uphawu "@" phakathi koqhagamshelwano olubini (umz. "SnO2@NiO") lubonisa ukuba i-scaffold material (NiO) ihonjiswe nge-SnO2 yohlobo lwe-sensor yohlobo lwe-II.I-slash (umzekelo, i-“NiO/SnO2”) ibonisa uhlobo lwe-III uyilo lwesivamvo.
Kwizinzwa zegesi ezisekelwe kwii-composites ze-MOS, izinto ezimbini ze-MOS zisasazwa ngokungenamkhethe phakathi kwee-electrodes.Iindlela ezininzi zokwenza izinto zenziwe ukuze kulungiswe i-MOS composites, kubandakanywa i-sol-gel, i-coprecipitation, i-hydrothermal, i-electrospinning, kunye neendlela zokuxuba ngomatshini98,102,103,104.Kungekudala, i-metal-organic frameworks (i-MOFs), iklasi yezinto ezibunjiweyo ze-crystalline eziqulunqwe ngamaziko esinyithi kunye ne-organic linkers, zisetyenziswe njengeetemplates zokwenziwa kwee-MOS composites105,106,107,108.Kuyafaneleka ukuba uqaphele ukuba nangona ipesenti ye-MOS composites iyafana, iimpawu zovakalelo zingahluka kakhulu xa usebenzisa iinkqubo ezahlukeneyo zokuvelisa.109,110 Ngokomzekelo, i-Gao et al.109 yenza i-sensor ezimbini ezisekelwe kwi-MoO3 ± SnO2 i-composites kunye ne-athomu efanayo. ( Mo: Sn = 1: 1.9 ) kwaye wafumanisa ukuba iindlela ezahlukeneyo zokwenza izinto zikhokelela kwiimvakalelo ezahlukeneyo.Shaposhnik et al.I-110 yabika ukuba ukusabela kwe-co-precipitated SnO2-TiO2 kwi-gaseous H2 yahluke kwizinto ezixutywe ngomatshini, nakwi-Sn / Ti ratio efanayo.Lo mahluko uvela ngenxa yokuba ubudlelwane phakathi kwe-MOP kunye ne-MOP ubukhulu be-crystallite buhluka ngeendlela ezahlukeneyo zokudibanisa109,110.Xa ubukhulu bengqolowa kunye nokuma kuhambelana ngokubhekiselele kwi-donor density kunye nohlobo lwe-semiconductor, impendulo kufuneka ihlale ifanayo ukuba i-geometry yoqhagamshelwano ayitshintshi i-110.Staerz et al.I-111 ibike ukuba iimpawu zokubona i-SnO2-Cr2O3 i-core-sheath (CSN) i-nanofibers kunye nomhlaba we-SnO2-Cr2O3 CSNs ziphantse zifana, zibonisa ukuba i-nanofiber morphology ayiniki nayiphi na inzuzo.
Ukongeza kwiindlela ezahlukeneyo zokwenziwa, iintlobo ze-semiconductor zee-MOSFET ezimbini ezahlukeneyo zikwachaphazela ubuntununtunu benzwa.Isenokwahlulwa kwakhona ibe ngamacandelo amabini ngokuxhomekeke ekubeni ezi MOSFET zimbini zodidi olufanayo lwesemiconductor (i-nn okanye i-pp junction) okanye iindidi ezahlukeneyo (pn junction).Xa i-gas sensors isekelwe kwii-composites ze-MOS zohlobo olufanayo, ngokutshintsha umlinganiselo we-molar we-MOS ezimbini, uphawu lokuphendula lovakalelo luhlala lungatshintshi, kwaye uvakalelo lwenzwa luyahluka ngokuxhomekeka kwinani le-nn- okanye i-pp-heterojunctions.Xa elinye icandelo lihamba phambili kwi-composite (umz. 0.9 ZnO-0.1 SnO2 okanye i-0.1 ZnO-0.9 SnO2), umjelo wokuqhuba unqunywe yi-MOS eyona nto, ebizwa ngokuba yi-homojunction conduction channel 92.Xa imilinganiselo yamacandelo amabini ithelekiswa, kucingelwa ukuba umjelo wokuqhuba ulawulwa yi-heterojunction98,102.Yamazoe et al.I-112,113 ibike ukuba ummandla we-heterocontact wamacandelo amabini unokuphucula kakhulu uvakalelo lwe-sensor kuba umqobo we-heterojunction owenziwe ngenxa yemisebenzi eyahlukeneyo yokusebenza yamacandelo inokulawula ngokufanelekileyo ukuhamba kwe-drift ye-sensor evezwe kwii-electron.Iigesi ezahlukeneyo ze-ambient 112,113.Kwikhiwane.Umzobo we-3a ubonisa ukuba i-sensors esekelwe kwi-SnO2-ZnO yezakhiwo ze-fibrous hierarchical ezinemixholo eyahlukeneyo ye-ZnO (ukusuka kwi-0 ukuya kwi-10 mol% Zn) inokukhetha ukukhetha i-ethanol.Phakathi kwabo, inzwa esekelwe kwi-SnO2-ZnO fibers (7 mol.% Zn) ibonise uvakalelo oluphezulu ngenxa yokubunjwa kwenani elikhulu le-heterojunctions kunye nokunyuka kwendawo ethile, eyandisa umsebenzi wokuguqula kunye nokuphucula. ubuntununtunu 90 Nangona kunjalo, ngokunyuka okungaphezulu kumxholo we-ZnO ukuya kwi-10 mol.%, i-microstructure ye-SnO2-ZnO edibeneyo ingakwazi ukugubungela iindawo zokuvula indawo kunye nokunciphisa i-sensor sensitivity85.Umkhwa ofanayo nawo ujongwa kwii-sensors ezisekelwe kwi-NiO-NiFe2O4 pp heterojunction composites kunye ne-Fe / Ni ratios ezahlukeneyo (Fig. 3b)114.
Imifanekiso ye-SEM yee-fibers ze-SnO2-ZnO (i-7 mol.% Zn) kunye nempendulo yenzwa kwiigesi ezahlukeneyo kunye noxinzelelo lwe-100 ppm kwi-260 ° C;Iimpendulo ze-54b zeenzwa ezisekelwe kwi-NiO ecocekileyo kunye ne-NiO-NiFe2O4 i-composites kwi-50 ppm yeegesi ezahlukeneyo, i-260 ° C;114 ( c) Umzobo weSchematic yenani leenodi kwi-xSnO2-(1-x) Co3O4 ukubunjwa kunye nokuchasana okuhambelanayo kunye nokusabela kovakalelo lwe-xSnO2-(1-x) Co3O4 ukwakheka kwi-10 ppm CO, i-acetone, i-C6H6 kunye ne-SO2 igesi kwi-350 °C ngokutshintsha umlinganiselo wemolar we-Sn/Co 98
Imixube ye-pn-MOS ibonisa ukuziphatha kobuntununtunu okwahlukileyo ngokuxhomekeke kumlinganiselo we-athomu ye-MOS115.Ngokubanzi, indlela yokuziphatha ye-MOS edibeneyo ixhomekeke kakhulu kwi-MOS esebenza njengejelo eliphambili lokuqhuba inzwa.Ngoko ke, kubaluleke kakhulu ukubonakalisa ukubunjwa kweepesenti kunye ne-nanostructure ye-composites.UKim et al.98 uqinisekisile esi sigqibo ngokudibanisa uluhlu lwe-xSnO2 ± (1-x) Co3O4 i-nanofibers edibeneyo nge-electrospinning kunye nokufunda iimpawu zabo zenzwa.Baye baqaphela ukuba ukuziphatha kwe-sensor ye-SnO2-Co3O4 edibeneyo itshintshile ukusuka kwi-n-uhlobo ukuya kwi-p-uhlobo ngokunciphisa ipesenti ye-SnO2 (Umfanekiso 3c) 98.Ukongezelela, i-heterojunction-controlled sensors (esekelwe kwi-0.5 SnO2-0.5 Co3O4) ibonise amazinga aphezulu okuhanjiswa kwe-C6H6 xa kuthelekiswa ne-homojunction-dominant sensors (umz, i-SnO2 ephezulu okanye i-Co3O4 sensors).Ukumelana okuphezulu kwe-0.5 ye-SnO2-0.5 ye-Co3O4 esekelwe kwinzwa kunye nekhono layo elikhulu lokumodareyitha ukuxhathisa i-sensor jikelele igalelo kwi-sensitivity yayo ephezulu kwi-C6H6.Ukongeza, iziphene ze-lattice ezingafaniyo ezivela kwi-SnO2-Co3O4 heterointerfaces zinokudala iindawo ezikhethekileyo zentengiso yeemolekyuli zegesi, ngaloo ndlela ziphucula impendulo yenzwa109,116.
Ukongeza kwi-semiconductor-uhlobo lwe-MOS, ukuziphatha okuchukumisayo kwee-MOS composites kunokwenziwa ngokwezifiso usebenzisa i-chemistry ye-MOS-117.U-Huo et al.117 wasebenzisa indlela elula yokubhaka i-soak-bake ukulungiselela i-Co3O4-SnO2 i-composites kwaye yafumanisa ukuba kwi-Co / Sn ye-molar ratio ye-10%, i-sensor ibonise impendulo yokufumanisa uhlobo lwe-p kwi-H2 kunye ne-n-type sensitivity to H2.impendulo.Iimpendulo ze-Sensor kwi-CO, i-H2S kunye ne-NH3 yeegesi ziboniswa kwi-Figure 4a117.Kwimilinganiselo ephantsi ye-Co / Sn, ii-homojunctions ezininzi zenza kwimida ye-SnO2 ± SnO2 ye-nanograin kwaye ibonise iimpendulo ze-n-type sensor kwi-H2 (Imifanekiso 4b, c) 115.Ngokunyuka kwe-Co / Sn ratio ukuya kwi-10 mol.%, endaweni ye-SnO2-SnO2 i-homojunctions, ezininzi ii-heterojunctions ze-Co3O4-SnO2 zenziwe ngaxeshanye (umzobo 4d).Ekubeni i-Co3O4 ingasebenzi ngokubhekiselele kwi-H2, kwaye i-SnO2 iphendula ngamandla kunye ne-H2, ukusabela kwe-H2 kunye neentlobo ze-ionic ze-oksijini zenzeka kakhulu phezu kwe-SnO2117.Ngoko ke, ii-electron zifudukela kwi-SnO2 kunye ne-Ef SnO2 itshintshela kwibhendi yokuqhuba, ngelixa i-Ef Co3O4 ihlala ingatshintshi.Ngenxa yoko, ukuchasana kwe-sensor kwanda, kubonisa ukuba izinto ezinomlinganiselo ophezulu we-Co / Sn zibonisa ukuziphatha kohlobo lwe-p (umzobo 4e).Ngokwahlukileyo, i-CO, i-H2S, kunye ne-NH3 iigesi zisabela ngeentlobo ze-oksijini ze-ionic kwiindawo ze-SnO2 kunye ne-Co3O4, kwaye ii-electron zihamba ukusuka kwi-gas ukuya kwi-sensor, okubangelwa ukuncipha kokuphakama komqobo kunye ne-n-type sensitivity (Fig. 4f)..Oku kuziphatha kwenzwa eyahlukileyo kungenxa ye-reactivity eyahlukileyo ye-Co3O4 kunye neegesi ezahlukeneyo, eziye zaqinisekiswa ngakumbi nguYin et al.118 .Ngokufanayo, uKatoch et al.I-119 ibonise ukuba ii-composites ze-SnO2-ZnO zinokukhethwa kakuhle kunye novakalelo oluphezulu kwi-H2.Oku kuziphatha kwenzeka ngenxa yokuba ii-athomu ze-H zinokubhengezwa ngokulula kwizikhundla ze-O ze-ZnO ngenxa ye-hybridization enamandla phakathi kwe-s-orbital ye-H kunye ne-p-orbital ye-O, ekhokelela kwi-metallization ye-ZnO120,121.
i-Co/Sn-10% ijika eliguquguqukayo lokumelana neegesi eziqhelekileyo zokunciphisa ezifana ne-H2, CO, NH3 kunye ne-H2S, b, c Co3O4/SnO2 i-composite sensing mechanism diagram ye-H2 kwi-low% m.I-Co/Sn, i-df Co3O4 yokufunyanwa kweMechanism ye-H2 kunye ne-CO, i-H2S kunye ne-NH3 ene-composite ephezulu ye-Co/Sn/SnO2
Ngoko ke, sinokuphucula uvakalelo lwe-sensor ye-I-type ngokukhetha iindlela ezifanelekileyo zokwenza, ukunciphisa ubungakanani beenkozo ze-composites, kunye nokwandisa umlinganiselo we-molar we-MOS composites.Ukongeza, ukuqonda okunzulu kwekhemistri yezinto ezibuthathaka kunokuphucula ngakumbi ukukhethwa kwenzwa.
Uhlobo lwe-II lwezakhiwo ze-sensor sesinye isakhiwo se-sensor esithandwayo esingasebenzisa izinto ezahlukeneyo ze-nanostructured, ezibandakanya enye "inkosi" nanomaterial kunye neyesibini okanye yesithathu nanomaterial.Ngokomzekelo, izinto ezinomlinganiselo omnye okanye ezimbini ezihlotshiswe nge-nanoparticles, i-core-shell (CS) kunye ne-multilayer heteronanostructured materials zisetyenziswa ngokuqhelekileyo kwi-sensor yohlobo lwe-II kwaye iya kuxutyushwa ngokubanzi apha ngezantsi.
Kwizinto zokuqala ze-heteronanostructure (i-heteronanostructure ehlotshisiwe), njengoko kuboniswe kwi-Fig. 2b (1), iziteshi eziqhubayo ze-sensor zixhunyiwe ngesiseko sesiseko.Ngenxa yokubunjwa kwe-heterojunctions, i-nanoparticles elungisiweyo inokubonelela ngeendawo ezisebenzayo kwi-gas adsorption okanye i-desorption, kwaye inokwenza njenge-catalysts ukuphucula ukusebenza kokuva109,122,123,124.U-Yuan et al.41 waqaphela ukuba ukuhlobisa i-WO3 nanowires kunye ne-CeO2 nanodots kunokubonelela ngeendawo ezininzi ze-adsorption kwi-CeO2 @ WO3 heterointerface kunye ne-CeO2 surface kunye nokuvelisa iintlobo ezininzi ze-oksijini ze-chemisorbed zokusabela nge-acetone.UGunawan et al.125. I-ultra-high-high sensitivity acetone sensor esekelwe kwi-one-dimensional Au @ α-Fe2O3 iphakanyisiwe kwaye ibonakaliswe ukuba uvakalelo lwe-sensor lulawulwa ngokusebenza kwee-molecule ze-O2 njengomthombo we-oksijini.Ubukho be-Au NPs bunokuthi busebenze njenge-catalyst ekhuthaza ukuchithwa kwee-molecule ze-oksijini kwi-oksijini ye-lattice ye-oxidation ye-acetone.Iziphumo ezifanayo zifunyenwe nguChoi et al.9 apho i-Pt catalyst yayisetyenziselwa ukwahlula iimolekyuli ze-oksijini ezidityanisiweyo zibe ziintlobo ze-oksijini ye-ionized kunye nokuphucula impendulo ebuthathaka kwi-acetone.Kwi-2017, iqela elifanayo lophando libonise ukuba i-nanoparticles ye-bimetallic iphumelele ngakumbi kwi-catalysis kune-nanoparticles enye yensimbi ehloniphekileyo, njengoko kuboniswe kuMzobo 5126. I-5a yinkqubo yokuvelisa i-platinum-based bimetallic (PtM) NPs isebenzisa iiseli ze-apoferritin ezineeseli ze-apoferritin ubungakanani obuqhelekileyo obungaphantsi kwe-3 nm.Emva koko, usebenzisa indlela ye-electrospinning, i-PtM @ WO3 i-nanofibers yafunyanwa ukwandisa ukuvakalelwa kunye nokukhetha kwi-acetone okanye i-H2S (umzobo 5b-g).Kungekudala, i-athomu enye ye-athomu (i-SACs) ibonise ukusebenza kakuhle kwe-catalytic kwintsimi ye-catalysis kunye nohlalutyo lwegesi ngenxa yobuninzi bokusetyenziswa kwe-athomu kunye nezakhiwo ze-elektroniki ezilungisiweyo127,128.Shin et al.I-129 isetyenziselwe i-Pt-SA i-anchored carbon nitride (MCN), i-SnCl2 kunye ne-PVP nanosheets njengemithombo yeekhemikhali ukulungiselela i-Pt @ MCN@SnO2 i-inline fibers ukufunyanwa kwegesi.Ngaphandle komxholo ophantsi kakhulu we-Pt@MCN (ukusuka kwi-0.13 wt.% ukuya kwi-0.68 wt.%), ukufunyanwa kwegesi ye-formaldehyde Pt@MCN@SnO2 ingaphezulu kunezinye iisampuli zereferensi (i-SnO2 emsulwa, i-MCN@SnO2 kunye ne-Pt NPs@ SnO2)..Lo msebenzi ugqwesileyo wokufumanisa unokubalelwa kubuchule obuphezulu beathom ye-Pt SA catalyst kunye nokhuselo oluncinci lweendawo ezisebenzayo ze-SnO2129.
Indlela ye-encapsulation ye-Apoferritin yokufumana i-PtM-apo (PtPd, PtRh, PtNi) nanoparticles;iipropati eziguquguqukayo zerhasi ezibuthathaka ze-bd pristine WO3, PtPd@WO3, PtRn@WO3, kunye ne-Pt-NiO@WO3 nanofibers;isekelwe, umzekelo, kwiipropati ezikhethiweyo zePtPd @ WO3, PtRn@WO3 kunye ne-Pt-NiO @ WO3 i-nanofiber sensors kwi-1 ppm yegesi ephazamisayo ye-126
Ukongezelela, i-heterojunctions eyenziwe phakathi kwezinto ze-scaffold kunye ne-nanoparticles nazo ziyakwazi ukulungelelanisa ngokufanelekileyo iziteshi zokuqhuba ngokusebenzisa i-radial modulation mechanism yokuphucula ukusebenza kwenzwa130,131,132.Kwikhiwane.Umzobo we-6a ubonisa iimpawu ze-sensor ye-SnO2 ecocekileyo kunye ne-Cr2O3 @ SnO2 nanowires yokunciphisa kunye neegesi ze-oxidizing kunye neendlela ezihambelanayo ze-sensor131.Xa kuthelekiswa ne-nanowires ecocekileyo ye-SnO2, impendulo ye-Cr2O3 @ SnO2 nanowires ekunciphiseni i-gases iphuculwe kakhulu, ngelixa impendulo kwiigesi ze-oxidizing iyancipha.Ezi ziganeko zihambelana ngokusondeleyo nokunciphisa kwendawo yeendlela zokuqhuba ze-SnO2 nanowires kwi-radial direction of the form heterojunction pn.Ukuxhatshazwa kwenzwa kunokulungiswa ngokulula ngokuguqula ububanzi be-EDL kumphezulu we-SnO2 nanowires ecocekileyo emva kokuvezwa ekunciphiseni kunye neegesi ze-oxidizing.Nangona kunjalo, kwi-Cr2O3 @ SnO2 nanowires, i-DEL yokuqala ye-SnO2 nanowires emoyeni inyuswa xa kuthelekiswa ne-SnO2 nanowires ecocekileyo, kwaye i-channel conduction igxininiswe ngenxa yokubunjwa kwe-heterojunction.Ngoko ke, xa i-sensor ibonakaliswe kwi-gas yokunciphisa, ii-electron ezibanjiweyo zikhutshwa kwi-SnO2 nanowires kwaye i-EDL iyancipha kakhulu, ibangele uvakalelo oluphezulu kune-SnO2 nanowires ecocekileyo.Ngokwahlukileyo, xa utshintshela kwigesi ene-oxidizing, ukwandiswa kwe-DEL kukhawulelwe, okubangela uvakalelo oluphantsi.Iziphumo ezifanayo zokuphendula ezinzwayo zabonwa nguChoi et al., 133 apho i-SnO2 nanowires ehlotshiswe nge-p-uhlobo lwe-WO3 nanoparticles ibonise ukuphuculwa kakhulu kwempendulo yeemvakalelo ekunciphiseni iigesi, ngelixa i-n-decorated SnO2 sensors yayiphucule ukuvakalelwa kwiigesi ze-oxidizing.I-TiO2 nanoparticles (Umfanekiso 6b) 133. Esi siphumo sibangelwa ikakhulu kwimisebenzi eyahlukeneyo ye-SnO2 kunye ne-MOS (TiO2 okanye i-WO3) nanoparticles.Kwi-p-type (n-type) nanoparticles, umjelo wokuqhuba we-framework material (SnO2) yandisa (okanye izivumelwano) kwi-radial direction, kwaye emva koko, phantsi kwesenzo sokunciphisa (okanye i-oxidation), ukwandiswa okuqhubekayo (okanye ukunciphisa) ye-channel conduction ye-SnO2 - i-rib) yegesi (umzobo 6b).
Indlela yokumodareyitha iRadi eyenziwe yiLF MOS elungisiweyo.isiShwankathelo seempendulo zegesi kwi-10 ppm yokunciphisa kunye ne-oxidizing iigesi ezisekelwe kwi-SnO2 ecocekileyo kunye ne-Cr2O3 @ SnO2 nanowires kunye nemizobo ehambelanayo ye-sensing ye-schematic diagrams;kunye nezicwangciso ezihambelanayo ze-WO3 @ SnO2 nanorods kunye neendlela zokufumanisa133
Kwizixhobo ze-bilayer kunye ne-multilayer heterostructure, i-channel conduction yesixhobo ilawulwa ngumaleko (ngokuqhelekileyo umaleko ongezantsi) ngokuqhagamshelana ngokuthe ngqo kunye ne-electrodes, kunye ne-heterojunction eyenziwe kwi-interface yamacandelo amabini inokulawula ukuhanjiswa komgangatho ongezantsi. .Ngoko ke, xa iigesi zisebenzisana nomgangatho ophezulu, zinokuchaphazela kakhulu iziteshi zokuqhuba umgca ongezantsi kunye nokumelana ne-134 yesixhobo.Ngokomzekelo, uKumar et al.I-77 ichaze ukuziphatha okuchaseneyo kwe-TiO2@NiO kunye ne-NiO@TiO2 i-double layers ye-NH3.Lo mahluko uvela ngenxa yokuba iziteshi zokuqhuba ze-sensor ezimbini zilawula kwiingqimba zezixhobo ezahlukeneyo (i-NiO kunye ne-TiO2, ngokulandelanayo), kwaye ke iinguqu kwiindlela zokuqhuba eziphantsi zihluke77.
I-Bilayer okanye i-heteronanostructures ye-multilayer idla ngokuveliswa ngokutshiza, i-atomic layer deposition (ALD) kunye ne-centrifugation56,70,134,135,136.Ubukhulu befilimu kunye nommandla woqhagamshelwano wezinto ezimbini zinokulawulwa kakuhle.Amanani 7a kunye ne-b abonisa i-NiO@SnO2 kunye ne-Ga2O3 @ WO3 nanofilms efunyenwe ngokutshiza ukufumanisa i-ethanol135,137.Nangona kunjalo, ezi ndlela ngokubanzi zivelisa iifilimu ezisicaba, kwaye ezi bhanyabhanya zisicaba azikhathazeki kangako kunezixhobo ze-3D ze-nanostructured ngenxa yendawo yazo ephantsi ethile kunye nokungena kwegesi.Ngoko ke, isicwangciso sesigaba se-liquid sokwenza iifilimu ze-bilayer kunye nemigangatho eyahlukeneyo iye yacetywayo ukuba kuphuculwe ukusebenza kwengqiqo ngokunyusa indawo ethile yendawo41,52,138.I-Zhu et al139 edibeneyo yokutshiza kunye nobuchule be-hydrothermal ukuvelisa i-nanowires eyalelwe kakhulu ye-ZnO phezu kwe-SnO2 nanowires (ZnO@SnO2 nanowires) ukufumanisa i-H2S (umzobo 7c).Impendulo yayo kwi-1 ppm H2S ngamaxesha e-1.6 aphezulu kuneyenzwa esekelwe kwi-sputtered ZnO@SnO2 nanofilms.ULiu et al.I-52 ibike i-sensor ye-H2S ephezulu yokusebenza usebenzisa i-step-step in situ chemical deposition method ukwenza i-hierarchical SnO2 @ NiO nanostructures elandelwa yi-thermal annealing (Fig. 10d).Xa kuthelekiswa neefilim ze-SnO2@NiO bilayer eziqhelekileyo ezitshiziweyo, ukusebenza kovakalelo lwesakhiwo se-bilayer se-SnO2@NiO siphuculwe kakhulu ngenxa yokunyuka kwendawo ethile52,137.
Inzwa yegesi ephindwe kabini esekelwe kwiMOS.NiO@SnO2 nanofilm yokufunyanwa kwe-ethanol;137b Ga2O3@WO3 nanofilm yokufunyanwa kwe-ethanol;I-135c iodolwe kakhulu i-SnO2@ZnO bilayer i-hierarchical structure yobhaqo lwe-H2S;I-139d SnO2@NiO bilayer ubume benqanaba lokubona i-H2S52.
Kuhlobo lwezixhobo ze-II ezisekelwe kwi-core-shell heteronanostructures (CSHNs), indlela yokuva inzima ngakumbi, ekubeni iziteshi zokuqhuba azikhawulelwanga kwigobolondo yangaphakathi.Bobabini indlela yokuvelisa kunye nobukhulu (hs) bepakethe inokugqiba indawo yeendlela zokuqhuba.Ngokomzekelo, xa usebenzisa iindlela ze-bottom-up synthesis, iziteshi zokuqhuba zivame ukukhawulelwa kwi-core yangaphakathi, efana nesakhiwo kwi-two-layer okanye i-multilayer yezixhobo zezixhobo (umzobo 2b (3)) 123, 140, 141, 142, 143. Xu et al.I-144 ibike indlela esezantsi yokufumana i-CSHN NiO @ α-Fe2O3 kunye ne-CuO@α-Fe2O3 ngokufaka ungqimba lwe-NiO okanye i-CuO NPs kwi-α-Fe2O3 nanorods apho umzila wokuqhuba ukhawulelwe yinxalenye ephakathi.(nanorods α-Fe2O3).ULiu et al.I-142 iphinde yaphumelela ekuthinteleni umjelo wokuqhuba ukuya kwindawo ephambili ye-CSHN TiO2 @ Si ngokufaka i-TiO2 kuluhlu olulungisiweyo lwe-silicon nanowires.Ngoko ke, ukuziphatha kwayo kokuva (uhlobo lwe-p okanye uhlobo lwe-n) kuxhomekeke kuphela kuhlobo lwe-semiconductor ye-silicon nanowire.
Nangona kunjalo, uninzi lwezinzwa ezisekelwe kwi-CSHN (Umfanekiso we-2b (4)) zenziwe ngokugqithisela iipowders zezinto ezidibeneyo ze-CS kwiichips.Kule meko, indlela yokuqhuba inzwa ichaphazeleka ngobuninzi bezindlu (hs).Iqela likaKim liphande isiphumo se-hs ekusebenzeni kokubonwa kwegesi kwaye licebise indlela yokufumanisa enokwenzeka100,112,145,146,147,148. Kukholelwa ukuba izinto ezimbini zinegalelo kwindlela yokuvakalelwa kwesi sakhiwo: (1) i-radial modulation ye-EDL yegobolondo kunye (2) ne-electric field smearing effect (Fig. 8) 145. Abaphandi bakhankanya ukuba umjelo wokuqhuba. yabathwali ikakhulu ivalelwe umaleko weqokobhe xa hs > λD yomaleko weqokobhe145. Kukholelwa ukuba izinto ezimbini zinegalelo kwindlela yokuvakalelwa kwesi sakhiwo: (1) i-radial modulation ye-EDL yegobolondo kunye (2) ne-electric field smearing effect (Fig. 8) 145. Abaphandi bakhankanya ukuba umjelo wokuqhuba. yabathwali ikakhulu ivalelwe umaleko weqokobhe xa hs > λD yomaleko weqokobhe145. Считается, что в механизме восприятия этой структуры участвуют два фактора: (1) радиальная модуляция ДЭС оболочки и (2) эффект размытия электрического поля (рис. 8) 145. Исследователи отметили, что канал проводимости носителей в основном приурочено к оболочке, когда hs > λD оболочки145. Kukholelwa ukuba izinto ezimbini zibandakanyeka kwindlela yokuqonda kwesi sakhiwo: (1) i-radial modulation ye-EDL yegobolondo kunye (2) nomphumo wokufiphalisa indawo yombane (umzobo 8) 145. Abaphandi baqaphele ukuba umjelo wokuqhuba ophetheyo uvalelwe ikakhulu kwiqokobhe xa hs > λD amaqokobhe145.Kukholelwa ukuba izinto ezimbini zinegalelo kwindlela yokufumanisa kwesi sakhiwo: (1) i-radial modulation ye-DEL yegobolondo kunye (2) umphumo we-electric field smearing (Umfanekiso 8) 145.研究人员提到传导通道当壳层的hs > λD145 时，载流子的数量主要局限于壳层。 > λD145 时，载流子的数量主要局限于壳层。 Исследователи отметили, что канал проводимости Когда hs > λD145 оболочки, количество носителей в основном ограничено оболочкой. Abaphandi baqaphele ukuba umjelo wokuqhuba Xa i-hs> λD145 yegobolondo, inani labathwali likhawulelwe ngokukodwa kwigobolondo.Ngoko ke, kwi-modulation resistive ye-sensor esekelwe kwi-CSHN, i-radial modulation ye-cladding DEL iphumelela (Umfanekiso 8a).Nangona kunjalo, kwi-hs ≤ λD yegobolondo, iinqununu ze-oksijini ezibhengezwa yigobolondo kunye ne-heterojunction eyenziwe kwi-CS heterojunction iphelile ngokupheleleyo kwii-electron. Ke ngoko, umjelo wokuqhuba awukho kuphela ngaphakathi kweqokobhe leqokobhe kodwa nakwinxalenye engundoqo, ngakumbi xa hs < λD yomaleko weqokobhe. Ke ngoko, umjelo wokuqhuba awukho kuphela ngaphakathi kweqokobhe leqokobhe kodwa nakwinxalenye engundoqo, ngakumbi xa hs < λD yomaleko weqokobhe. Поэтому канал проводимости располагается не только внутри оболочечного слоя, но и частично в сердцевинной части, особенное причение причение. Ngoko ke, umjelo wokuqhuba awukho kuphela ngaphakathi kwinqanaba leqokobhe, kodwa kunye nenxalenye yecandelo eliphambili, ngakumbi kwi-hs < λD yoluhlu lwegobolondo.因此，传导通道不仅位于壳层内部，而且部分位于芯部，尤其是当壳层的hs < λD 时. hs < λD 时. Поэтому канал проводимости располагается не только внутри оболочки, но и частично в сердцевине, особенно при hs < λD оболочки. Ngoko ke, umjelo wokuqhuba awukho kuphela ngaphakathi kwegobolondo, kodwa kunye nenxalenye engundoqo, ngakumbi kwi-hs < λD yegobolondo.Kule meko, zombini igobolondo ye-electron ephele ngokupheleleyo kunye nenxalenye engundoqo yomaleko inceda ukumodareyitha ukuchasana kwayo yonke i-CSHN, okukhokelela kwisiphumo somsila wombane (Fig. 8b).Olunye uphando lusebenzise i-EDL i-volume fraction concept concept endaweni yomsila wentsimi yombane ukuhlalutya i-hs effect100,148.Ukuthatha le minikelo mibini ingqalelo, ukumodareyitha iyonke yokumelana CSHN ifikelela kwixabiso layo elikhulu xa hs ithelekiseka kwi sheath λD, njengoko kubonisiwe Fig. 8c.Ke ngoko, ezona hs ze-CSHN zinokusondela kwiqokobhe elithi λD, elihambelana nokuqwalaselwa kovavanyo99,144,145,146,149.Izifundo ezininzi zibonise ukuba i-hs inokuchaphazela uvakalelo lwe-CSHN-based pn-heterojunction sensors40,148.Li et al.148 kunye noBai et al.I-40 iphande ngokucwangcisiweyo umphumo we-hs ekusebenzeni kwe-pn-heterojunction CSHN sensors, ezifana ne-TiO2@CuO kunye ne-ZnO@NiO, ngokuguqula umjikelezo we-ALD we-cladding.Ngenxa yoko, ukuziphatha kweemvakalelo kwatshintsha ukusuka kuhlobo lwe-p ukuya kuhlobo lwe-n ngokunyuka kwe-hs40,148.Oku kuziphatha kubangelwa ukuba ekuqaleni (kunye nenani elilinganiselwe lemijikelezo ye-ALD) i-heterostructures ingathathwa njenge-heteronanostructures elungisiweyo.Ngaloo ndlela, ijelo lokuqhuba lilinganiselwe ngumaleko ongundoqo (i-p-uhlobo lwe-MOSFET), kwaye inzwa ibonisa ukuziphatha kohlobo lwe-p.Njengoko inani lemijikelo ye-ALD lisanda, i-cladding layer (i-n-type MOSFET) iba yinto eqhubekayo kwaye isebenze njengejelo lokuqhuba, elikhokelela kubuntununtunu bohlobo lwe-n.Ukuziphatha okufanayo kwenguqu yengqondo kuye kwabikwa kwi-pn branched heteronanostructures 150,151.Zhou et al.I-150 iphande uvakalelo lwe-Zn2SnO4@Mn3O4 i-heteronanostructures ye-branched ngokulawula umxholo we-Zn2SnO4 kumphezulu we-Mn3O4 nanowires.Xa i-nuclei ye-Zn2SnO4 yenziwe kwindawo ye-Mn3O4, i-p-type sensitivity yabonwa.Ngokunyuka okuqhubekayo kumxholo we-Zn2SnO4, inzwa esekelwe kwi-branched Zn2SnO4 @ Mn3O4 heteronanostructures itshintshela kwindlela yokuziphatha ye-n-type.
Inkcazo yengqiqo yendlela yokusebenza ye-sensor ye-CS nanowires ibonisiwe.a Ukumodareyitha okuchasayo ngenxa yokumodareyithwa kweradial yamaqokobhe e-electron-ephelile, b Isiphumo esibi sokuthambisa ukumodareyitha ukuchasa, kunye c Ukumodareyitha kokumelana ngokupheleleyo kwe-CS nanowires ngenxa yendibaniselwano yazo zombini iziphumo 40
Ukuqukumbela, i-sensors zohlobo lwe-II ziquka ezininzi ezahlukeneyo ze-hierarchical nanostructures, kwaye ukusebenza kwenzwa kuxhomekeke kakhulu kulungiselelo lweendlela zokuqhuba.Ngoko ke, kubalulekile ukulawula isikhundla somjelo wokuqhuba inzwa kunye nokusebenzisa imodeli ye-MOS efanelekileyo ye-heteronanostructured ukufunda indlela yokubona eyandisiweyo yohlobo lwe-II yenzwa.
Uhlobo lwe-III izakhiwo ze-sensor aziqhelekanga kakhulu, kwaye umjelo wokuqhuba usekelwe kwi-heterojunction eyenziwe phakathi kwee-semiconductors ezimbini ezixhunywe kwii-electrodes ezimbini, ngokulandelanayo.Izakhiwo zesixhobo ezizodwa zidla ngokufunyanwa ngokusebenzisa ubuchule be-micromachining kwaye iindlela zabo zokuva zihluke kakhulu kwizakhiwo ezimbini zangaphambili zenzwa.Ijika le-IV le-sensor yoHlobo lwe-III ngokuqhelekileyo ibonisa iimpawu zokulungiswa okuqhelekileyo ngenxa yokwakheka kwe-heterojunction48,152,153.I-I-V ye-curve ye-curve ye-heterojunction efanelekileyo inokuchazwa ngumatshini we-thermionic wokukhutshwa kwe-electron phezu kokuphakama komqobo we-heterojunction152,154,155.
apho Va yi-voltage bias, A yindawo yesixhobo, k yiBoltzmann engaguqukiyo, T yiqondo lobushushu elipheleleyo, q ngumthwali wentlawulo, i-Jn kunye ne-Jp ngumngxuma kunye ne-electron diffusion yangoku yoxinaniso, ngokulandelelana.IS imele i-reverse saturation yangoku, echazwa njenge: 152,154,155
Ngoko ke, umbane opheleleyo we-pn heterojunction uxhomekeke ekutshintsheni ukuxinwa kwabathwali bentlawulo kunye noshintsho ekuphakameni komqobo we-heterojunction, njengoko kuboniswe kwii-equations (3) kunye (4) 156
apho i-nn0 kunye ne-pp0 luxinzelelo lwee-electron (imingxuma) kuhlobo lwe-n (p-type) MOS, \(V_{bi}^0\) inamandla okwakhelwa ngaphakathi, i-Dp (Dn) yi-coefficient yokusasazwa kwe ii-electron (imingxuma), i-Ln (Lp) ubude bokusabalalisa kwee-electron (imingxuma), i-ΔEv (ΔEc) yinguqu yamandla ye-valence band (i-conduction band) kwi-heterojunction.Nangona ingxinano yangoku ilingana noxinaniso lomthwali, i-exponentially inversely ihambelana ne \(V_{bi}^0\).Ke ngoko, utshintsho olupheleleyo kuxinaniso lwangoku luxhomekeke kakhulu ekumodareyithweni kobude bomqobo we-heterojunction.
Njengoko kukhankanyiwe ngasentla, ukudalwa kwee-MOSFET ze-hetero-nanostructured (umzekelo, uhlobo lwe-I kunye nohlobo lwezixhobo ze-II) kunokuphucula kakhulu ukusebenza kwenzwa, kunokuba kumacandelo ngamanye.Kwaye kuhlobo lwe-III izixhobo, impendulo ye-heteronanostructure ingaba phezulu kumacandelo amabini48,153 okanye ngaphezulu kwecandelo elinye76, kuxhomekeke kwimichiza yezinto eziphathekayo.Iingxelo ezininzi ziye zabonisa ukuba impendulo ye-heteronanostructures iphezulu kakhulu kunecandelo elilodwa xa enye yamacandelo ingabonakali kwi-gas48,75,76,153 ekujoliswe kuyo.Kule meko, igesi ekujoliswe kuyo iya kusebenzisana kuphela kunye nomgangatho obuthathaka kwaye ibangele ukutshintshwa kwe-Ef yoluhlu olubucayi kunye noshintsho ekuphakameni komqobo we-heterojunction.Emva koko umthamo opheleleyo wesixhobo uya kutshintsha kakhulu, kuba uhambelana ngokuphambene nokuphakama komqobo we-heterojunction ngokwe-equation.(3) kunye (4) 48,76,153.Nangona kunjalo, xa zombini udidi lwe-n kunye nohlobo lwe-p-uhlobo lunovakalelo kwirhasi ekujoliswe kuyo, ukusebenza kokufumanisa kunokuba kwindawo ethile phakathi.UJosé et al.76 wavelisa i-porous NiO / SnO2 ifilimu ye-NO2 inzwa ngokutshiza kwaye yafumanisa ukuba i-sensor sensitivity yayiphezulu kuphela kune-sensor esekelwe kwi-NiO, kodwa iphantsi kune-sensor esekelwe kwi-SnO2.isivamvo.Le nto ibangelwa kukuba i-SnO2 kunye ne-NiO zibonisa ukusabela okuchaseneyo ne-NO276.Kwakhona, ngenxa yokuba la macandelo mabini aneemvakalelo ezahlukeneyo zerhasi, anokuba nomkhwa ofanayo wokubona i-oxidizing kunye nokunciphisa iigesi.Ngokomzekelo, uKwon et al.I-157 icetywayo i-NiO / SnO2 inzwa yegesi ye-pn-heterojunction nge-oblique sputtering, njengoko kuboniswe kumfanekiso we-9a.Okubangel 'umdla kukuba, i-NiO / SnO2 i-pn-heterojunction sensor ibonise i-sensitivity efanayo ye-H2 kunye ne-NO2 (umzobo 9a).Ukusombulula esi siphumo, uKwon et al.I-157 iphande ngokucwangcisiweyo indlela i-NO2 kunye ne-H2 itshintsha ngayo i-concentrations ye-carrier kunye ne-tuned \ (V_ {bi} ^ 0 \) zombini izixhobo usebenzisa i-IV-characteristics kunye ne-computer simulations (Fig. 9bd).Amanani 9b kunye no-c abonisa amandla e-H2 kunye ne-NO2 ukutshintsha ubuninzi be-carrier of sensors esekelwe kwi-p-NiO (pp0) kunye ne-n-SnO2 (nn0), ngokulandelanayo.Babonisa ukuba i-pp0 ye-p-uhlobo lwe-NiO yatshintsha kancinci kwindawo ye-NO2, ngelixa yatshintsha kakhulu kwindawo ye-H2 (Umfanekiso 9b).Nangona kunjalo, kuhlobo lwe-n-SnO2, i-nn0 iziphatha ngendlela eyahlukileyo (Umfanekiso 9c).Ngokusekelwe kwezi ziphumo, ababhali baphetha ukuba xa i-H2 isetyenziswe kwi-sensor esekelwe kwi-NiO / SnO2 pn heterojunction, ukwanda kwe-nn0 kubangele ukwanda kwe-Jn, kwaye \ (V_ {bi} ^ 0 \) ukunciphisa impendulo (Umfanekiso 9d).Emva kokuvezwa kwi-NO2, zombini ukuncipha okukhulu kwi-nn0 kwi-SnO2 kunye nokunyuka okuncinci kwi-pp0 kwi-NiO kukhokelela ekunciphiseni okukhulu kwi- \ ( V_ {bi} ^ 0 \ ), okuqinisekisa ukwanda kwempendulo ye-sensory (Fig. 9d) ) 157 Ekugqibeleni, utshintsho kwingqwalasela yabathwali kunye \ (V_{bi} ^ 0 \) ikhokelela ekutshintsheni kwinani elipheleleyo langoku, elichaphazela ngakumbi ukukwazi ukubona.
Indlela yokubona inzwa yegesi isekelwe kwisakhiwo sesixhobo soHlobo lwe-III.Ukuskena i-electron microscopy (SEM) imifanekiso ye-cross-sectional, i-p-NiO / n-SnO2 isixhobo se-nanocoil kunye neempawu zenzwa ze-p-NiO / n-SnO2 i-nanocoil heterojunction sensor kwi-200 ° C ye-H2 kunye ne-NO2;b , i-SEM ye-cross-sectional ye-c-device, kunye neziphumo zokulinganisa zesixhobo esine-p-NiO b-layer kunye ne-n-SnO2 c-layer.I-sensor ye-b p-NiO kunye ne-c n-SnO2 yokulinganisa i-sensor kwaye ifanise iimpawu ze-I-V emoyeni owomileyo kwaye emva kokuvezwa kwi-H2 kunye ne-NO2.Imephu ye-dimensional-dimensional ye-b-hole density kwi-p-NiO kunye nemephu ye-c-electrons kwi-n-SnO2 umaleko kunye nesikali sombala zenziwe imodeli ngokusebenzisa i-software ye-Sentaurus TCAD.d Iziphumo zokulinganisa ezibonisa imephu ye-3D ye-p-NiO/n-SnO2 emoyeni owomileyo, i-H2 kunye ne-NO2157 kwindawo.
Ukongeza kwiimpawu zeekhemikhali zezinto ngokwazo, isakhiwo sohlobo lwe-III isixhobo sibonisa ukuba kunokwenzeka ukudala i-self-powered sensors yegesi, engenakwenzeka nge-Type I kunye ne-Type II izixhobo.Ngenxa yendawo yabo yombane (BEF), izakhiwo ze-pn heterojunction diode ziqhele ukusetyenziswa ukwakha izixhobo ze-photovoltaic kunye nokubonisa amandla okwenza i-self-powered photoelectric gas sensors kwiqondo lokushisa eliphantsi kokukhanya74,158,159,160,161.I-BEF kwi-heterointerface, ebangelwa ngumahluko kumanqanaba e-Fermi ezinto eziphathekayo, iphinde ibe negalelo ekuhlukaneni kwezibini ze-electron-hole.Inzuzo ye-self-powered photovoltaic gas sensor yinkqubo yayo ephantsi yokusetyenziswa kwamandla njengoko inokuthatha amandla okukhanya okukhanyayo kwaye emva koko izilawule okanye ezinye izixhobo ezincinci ngaphandle kwesidingo somthombo wamandla wangaphandle.Ngokomzekelo, i-Tanuma kunye ne-Sugiyama162 yenze i-NiO / ZnO pn heterojunctions njengeeseli zelanga ukuze kusebenze i-SnO2-based based polycrystalline sensors CO2.uGad et al.I-74 ibike i-self-powered photovoltaic gas sensor esekelwe kwi-Si / ZnO @ CdS pn heterojunction, njengoko kuboniswe kwi-Fig. 10a.I-ZnO nanowires ezijonge ngokuthe nkqo zakhuliswa ngokuthe ngqo kuhlobo lwe-silicon substrates ukwenza iSi/ZnO pn heterojunctions.Emva koko i-nanoparticles ye-CdS yatshintshwa kumphezulu we-ZnO nanowires ngokuguqulwa kwendawo yeekhemikhali.Kwikhiwane.I-10a ibonisa iziphumo zempendulo ye-sensor ye-Si / ZnO@CdS ngaphandle kwe-intanethi ye-O2 kunye ne-ethanol.Ngaphantsi kokukhanya, i-voltage ye-open-circuit (Voc) ngenxa yokuhlukana kwee-electron-hole pairs ngexesha le-BEP kwi-Si / ZnO heterointerface inyuka ngokuhambelana nenani le-diodes edibeneyo74,161.I-Voc inokumelwa yi-equation.(5) 156,
apho i-ND, i-NA, kunye ne-Ni zizigxina zabaxhasi, abamkeli, kunye nabathwali be-intrinsic, ngokulandelanayo, kunye no-k, T, kunye no-q bafana neeparitha ezifanayo kwi-equation yangaphambili.Xa bevezwe kwiigesi ze-oxidizing, bakhupha ii-electron kwi-ZnO nanowires, okukhokelela ekunciphiseni kwi- \ (N_D ^ {ZnO} \) kunye ne-Voc.Ngakolunye uhlangothi, ukunciphisa igesi kubangele ukwanda kweVoc (Fig. 10a).Xa uhlobisa i-ZnO kunye ne-CdS nanoparticles, i-electron e-photoexcited kwi-nanoparticles ye-CdS ijojowe kwi-band conduction ye-ZnO kwaye idibanise ne-gas adsorbed, ngaloo ndlela inyusa i-perception performance74,160.I-self-powered self-powered photovoltaic gas sensor esekelwe kwi-Si / ZnO yabikwa nguHoffmann et al.160, 161 (Umfanekiso 10b).Le nzwa inokulungiswa ngokusebenzisa umgca we-amine-functionalized ZnO nanoparticles ([3-(2-aminoethylamino) propyl] trimethoxysilane) (amino-functionalized-SAM) kunye ne-thiol ((3-mercaptopropyl) -esebenzayo, ukulungisa umsebenzi womsebenzi. yerhasi ekujoliswe kuyo ekubhaqweni okukhethiweyo kwe-NO2 (trimethoxysilane) (thiol-functionalized-SAM)) (Umfanekiso 10b) 74,161.
I-self-powered photoelectric gas sensor esekelwe kwisakhiwo sohlobo lwe-III isixhobo.i-Self-powered photovoltaic gas sensor esekelwe kwi-Si / ZnO @ CdS, i-self-powered sensing mechanism kunye nempendulo yenzwa kwi-oxidized (O2) kunye nokunciphisa (1000 ppm ethanol) iigesi phantsi kwelanga;I-74b I-Self-powered photovoltaic gas sensor esekelwe kwi-Si ZnO / ZnO sensors kunye neempendulo zenzwa kwiigesi ezahlukeneyo emva kokusebenza kwe-ZnO SAM kunye ne-terminal amines kunye ne-thiols 161
Ngoko ke, xa kuxoxwa ngendlela enobucayi yohlobo lwe-III inzwa, kubalulekile ukumisela utshintsho ekuphakameni komqobo we-heterojunction kunye nokukwazi kwegesi ukuchaphazela ukugxininiswa komthwali.Ukongeza, ukukhanyisa kunokuvelisa abathwali beefoto abasabela ngeegesi, ezithembisa ukubonwa kwegesi esebenza ngokuzimeleyo.
Njengoko kuxoxiwe kolu hlaziyo lweencwadi, ezininzi ezahlukeneyo ze-MOS heteronanostructures zenziwe ukuze kuphuculwe ukusebenza kwenzwa.I-Web of Science Database yakhangelwa amagama angundoqo ahlukeneyo (i-metal oxide composites, i-core-sheath metal oxides, i-oxides yensimbi elayishiweyo, kunye ne-self-powered analyzers) kunye neempawu ezahlukileyo (ubuninzi, ubuntununtunu / ukukhethwa, amandla okuvelisa amandla, ukuvelisa) .Indlela Iimpawu ezintathu kwezi zixhobo zintathu ziboniswe kwiThebhile 2. Ingcamango yoyilo jikelele yeenzwa zegesi eziphezulu zixoxwa ngokuhlalutya izinto ezintathu eziphambili ezicetywayo nguYamazoe.Iindlela zeeSensors ze-MOS Heterostructure Ukuqonda izinto ezichaphazela izinzwa zegesi, iiparamitha ezahlukeneyo ze-MOS (umzekelo, ubungakanani beenkozo, ubushushu bokusebenza, isiphene kunye nokuxinana kwesithuba se-oxygen, iinqwelomoya zekristale ezivulekileyo) zihlolisiswe ngononophelo.Isakhiwo sesixhobo, esikwabaluleke kakhulu kwindlela yokuziphatha kwenzwa, ayihoywa kwaye ayixoxiswanga.Olu phononongo luxoxa ngeendlela ezisisiseko zokufumanisa iintlobo ezintathu eziqhelekileyo zesakhiwo sesixhobo.
Isakhiwo sobungakanani bengqolowa, indlela yokuvelisa, kunye nenani le-heterojunctions yezinto zokuva kwi-Sensor Type I inokuchaphazela kakhulu uvakalelo lwenzwa.Ukongezelela, ukuziphatha kwenzwa kuchaphazeleka ngumlinganiselo we-molar wamacandelo.Uhlobo lwe-II yezakhiwo zesixhobo (i-heteronanostructures yokuhlobisa, i-bilayer okanye iifilimu ezininzi, i-HSSNs) zizona zakhiwo zesixhobo ezidumileyo ezibandakanya amacandelo amabini okanye ngaphezulu, kwaye enye kuphela icandelo elixhunyiwe kwi-electrode.Kwesi sakhiwo sesixhobo, ukugqiba indawo yeendlela zokuqhuba kunye neenguqu zabo ezihambelanayo zibalulekile ekufundeni indlela yokuqonda.Ngenxa yokuba izixhobo zohlobo lwe-II ziquka ezininzi ezahlukeneyo ze-hierarchical heteronanostructures, iindlela ezininzi ezahlukeneyo zokuva ziye zacetywa.Kuhlobo lwe-sensory ye-III isakhiwo, umjelo wokuqhuba ulawulwa yi-heterojunction eyenziwe kwi-heterojunction, kwaye indlela yokuqonda ihluke ngokupheleleyo.Ngoko ke, kubalulekile ukumisela utshintsho ekuphakameni komqobo we-heterojunction emva kokuvezwa kwegesi ekujoliswe kuyo kwi-sensor ye-III.Ngolu yilo, i-self-powered photovoltaic gas sensors ingenziwa ukunciphisa ukusetyenziswa kwamandla.Nangona kunjalo, kuba inkqubo yangoku yokwenziwa iyinto entsonkothileyo kwaye ubuntununtunu busezantsi kakhulu kune-MOS-based ye-chemo-resistive gas sensors, kusekho inkqubela eninzi kuphando lwe-self-powered sensors yegesi.
Iinzuzo eziphambili zegesi ze-MOS zenzwa ezine-hierarchical heteronanostructures zisantya kunye novakalelo oluphezulu.Nangona kunjalo, ezinye iingxaki eziphambili zee-sensors zegesi ze-MOS (umzekelo, ukushisa okuphezulu kokusebenza, ukuzinza kwexesha elide, ukukhetha okungalunganga kunye nokuveliswa kwakhona, iziphumo zokufuma, njl.) zisekho kwaye zifuna ukulungiswa ngaphambi kokuba zisetyenziswe kwizicelo eziphathekayo.Iinzwa zerhasi zanamhlanje zeMOS zihlala zisebenza kumaqondo obushushu aphezulu kwaye zisebenzisa amandla amaninzi, nto leyo echaphazela ukuzinza kwexesha elide lenzwa.Kukho iindlela ezimbini eziqhelekileyo zokusombulula le ngxaki: (1) uphuhliso lwe-chips sensor yamandla aphantsi;(2) ukuphuhliswa kwezinto ezintsha ezinovakalelo ezinokusebenza kwiqondo lobushushu eliphantsi okanye nakwiqondo lobushushu begumbi.Enye indlela ekuphuhliseni iitshiphusi zenzwa yamandla aphantsi kukunciphisa ubungakanani benzwa ngokwenza iipleyiti zokufudumeza ezincinci ezisekwe kwiiseramics kunye nesilicon163.Iipleyiti zokufudumeza ezisekwe kwi-Ceramic zidla malunga ne-50-70 mV ngenzwa nganye, ngelixa i-silicon ephuculweyo esekelwe kwiipleyiti zokufudumeza ezincinci zinokutya kancinci njenge-2 mW ngenzwa nganye xa isebenza ngokuqhubekayo kwi-300 °C163,164.Ukuphuhliswa kwezinto ezintsha zokuva kuyindlela efanelekileyo yokunciphisa ukusetyenziswa kwamandla ngokunciphisa ubushushu bokusebenza, kwaye kunokuphucula ukuzinza kwenzwa.Njengoko ubukhulu be-MOS buqhubeka buncitshiswa ukwandisa uvakalelo lwe-sensor, ukuzinza kwe-thermal ye-MOS kuba ngumngeni omkhulu, onokukhokelela ekuqhubeni kwi-sensor signal165.Ukongezelela, ukushisa okuphezulu kukhuthaza ukusabalalisa kwezinto kwi-heterointerface kunye nokwakhiwa kwezigaba ezixubileyo, ezichaphazela iimpawu ze-elektroniki ze-sensor.Abaphandi baxela ukuba ubushushu obuphezulu bokusebenza kwenzwa bunokuncitshiswa ngokukhetha izixhobo ezifanelekileyo zokuva kunye nokuphuhlisa i-MOS heteronanostructures.Ukukhangela indlela yobushushu obuphantsi bokwenza i-crystalline MOS heteronanostructures yenye indlela ethembisayo yokuphucula uzinzo.
Ukukhethwa kwee-sensors ze-MOS ngomnye umba osebenzayo njengoko iigesi ezahlukeneyo zihlala kunye nerhasi ekujoliswe kuyo, ngelixa abenzi boluvo be-MOS bahlala benovelwano kwigesi enye kwaye bahlala bebonisa ubuntununtunu obunqamlezayo.Ke ngoko, ukunyusa ukukhethwa kwenzwa kwirhasi ekujoliswe kuyo kunye nakwezinye iigesi kubalulekile kwizicelo ezisebenzayo.Kwiminyaka embalwa edlulileyo, ukhetho luye lwaqwalaselwa ngokuyinxenye ngokwakhiwa kwezixhobo zegesi ezibizwa ngokuba "iimpumlo ze-electronic (E-nose)" ngokudibanisa ne-computational analysis algorithms ezifana ne-training vector quantization (LVQ), uhlalutyo lwecandelo eliphambili (PCA), njl. e.Iingxaki zesini.Izikwere eziNcinane zincinci (PLS), njl njl. 31, 32, 33, 34. Izinto ezimbini eziphambili (inani labenzi boluvo, ezinxulumene ngokusondeleyo nohlobo lwezinto zokuva, kunye nohlalutyo lokubala) zibalulekile ekuphuculeni amandla eempumlo zombane. ukuchonga iigesi169.Nangona kunjalo, ukwandisa inani leenzwa ngokuqhelekileyo kufuna iinkqubo ezininzi zokuvelisa eziyinkimbinkimbi, ngoko ke kubalulekile ukufumana indlela elula yokuphucula ukusebenza kweempumlo ze-elektroniki.Ukongeza, ukuguqula i-MOS kunye nezinye izinto kunokunyusa ukukhethwa kwenzwa.Ngokomzekelo, ukuchongwa okukhethiweyo kwe-H2 kunokufezekiswa ngenxa yomsebenzi omhle we-catalytic we-MOS eguqulwe ngeNP Pd.Kwiminyaka yakutshanje, abanye abaphandi baye bafaka umphezulu we-MOS MOF ukuphucula ukukhethwa kweenzwa ngokusebenzisa ukukhutshwa kobukhulu171,172.Iphefumlelwe ngulo msebenzi, ukusebenza kwezinto eziphathekayo kunokusombulula ingxaki yokukhetha.Nangona kunjalo, usemninzi umsebenzi ekufuneka wenziwe ekukhetheni izinto ezifanelekileyo.
Ukuphindaphinda kweempawu zeenzwa ezenziwe phantsi kweemeko ezifanayo kunye neendlela enye imfuneko ebalulekileyo kwimveliso enkulu kunye nokusetyenziswa okusebenzayo.Ngokuqhelekileyo, i-centrifugation kunye neendlela zokudipha ziindlela zeendleko eziphantsi zokwenza izinzwa zerhasi ephezulu.Nangona kunjalo, ngexesha lezi nkqubo, izinto ezithintekayo zivame ukudibanisa kunye nobudlelwane phakathi kwezinto ezithintekayo kunye ne-substrate iba buthathaka68, 138, 168. Ngenxa yoko, uvakalelo kunye nokuzinza kwenzwa kuyancipha kakhulu, kwaye ukusebenza kuphinda kuphinde kuphindwe.Ezinye iindlela zokwenza izinto ezifana ne-sputtering, i-ALD, i-pulsed laser deposition (PLD), kunye ne-vapor vapor deposition (PVD) ivumela ukuveliswa kwe-bilayer okanye iifilimu ze-MOS ezininzi ngokuthe ngqo kwi-silicon enepateni okanye i-alumina substrates.Ezi ndlela zobuchule zithintela ukwakhiwa kwezixhobo ezibuthathaka, ziqinisekisa ukuveliswa kwakhona kwenzwa, kwaye zibonise ukuba nokwenzeka kokuveliswa komgangatho omkhulu we-planar thin-film sensors.Nangona kunjalo, ubuntununtunu bezi filimu zicaba ziphantsi kakhulu kunezo ze-3D ze-nanostructured materials ngenxa yendawo encinci yendawo kunye ne-gas permeability ephantsi41,174.Izicwangciso ezitsha zokukhulisa i-MOS heteronanostructures kwiindawo ezithile kwii-microarrays ezicwangcisiweyo kunye nokulawula ngokuchanekileyo ubungakanani, ubukhulu, kunye ne-morphology yezixhobo ezibuthathaka zibaluleke kakhulu kwixabiso eliphantsi lokwenziwa kwe-wafer-level sensors kunye nokuphindaphinda okuphezulu kunye novakalelo.Ngokomzekelo, uLiu et al.I-174 icebise isicwangciso esihlangeneyo esiphezulu kunye nesezantsi-phezulu sokwenza i-crystallites ephezulu ngokukhula kwi-situ Ni (OH) i-nanowalls ye-2 kwiindawo ezithile..Ii-wafers ze-microburners.
Ukongezelela, kubalulekile ukuqwalasela umphumo womswakama kwi-sensor kwizicelo eziphathekayo.Iimolekyuli zamanzi zinokukhuphisana kunye neemolekyuli ze-oksijini kwiindawo ze-adsorption kwi-sensor materials kwaye zichaphazela uxanduva lwe-sensor yegesi ekujoliswe kuyo.Njengeoksijini, amanzi asebenza njengemolekyuli ngokusebenzisa i-sorption yomzimba, kwaye anokubakho ngendlela ye-hydroxyl radicals okanye amaqela e-hydroxyl kwiindawo ezahlukeneyo ze-oxidation ngokusebenzisa i-chemisorption.Ukongezelela, ngenxa yezinga eliphezulu kunye nomswakama oguquguqukayo wokusingqongileyo, impendulo ethembekileyo yenzwa kwigesi ekujoliswe kuyo yingxaki enkulu.Izicwangciso ezininzi ziye zaphuhliswa ukujongana nale ngxaki, njenge-gas preconcentration177, imbuyekezo yomswakama kunye neendlela ze-lattice cross-reactive lattice178, kunye neendlela zokumisa179,180.Nangona kunjalo, ezi ndlela zibiza kakhulu, zinzima, kwaye zinciphisa uvakalelo lwenzwa.Iindlela ezininzi ezingabizi kakhulu zicetyiwe ukucinezela iziphumo zokufuma.Ngokomzekelo, ukuhlobisa i-SnO2 kunye ne-Pd nanoparticles kunokukhuthaza ukuguqulwa kwe-oksijini ye-adsorbed kwiincinci ze-anionic, ngelixa i-SnO2 isebenza kunye nezinto ezinobudlelwane obuphezulu be-molecule yamanzi, njenge-NiO kunye ne-CuO, zimbini iindlela zokuthintela ukuxhomekeka komswakama kwi-molecule yamanzi..I-Sensors 181, 182, 183. Ukongezelela, umphumo womswakama unokuncitshiswa kwakhona ngokusebenzisa izinto ze-hydrophobic ukwenza iindawo ze-hydrophobic36,138,184,185.Nangona kunjalo, uphuhliso lwezinzwa zerhasi ezikwaziyo ukumelana nokufuma lusekwinqanaba lakwangoko, kwaye izicwangciso eziphucukileyo ziyafuneka ukulungisa le miba.
Ukuqukumbela, ukuphuculwa komsebenzi wokubona (umzekelo, ubuntununtunu, ukukhetha, ubushushu obuphantsi bokusebenza) kuye kwaphunyezwa ngokudala i-MOS heteronanostructures, kwaye iindlela ezahlukeneyo zokubona eziphuculweyo ziye zacetywa.Xa ufunda indlela yokuva yenzwa ethile, isakhiwo sejometri yesixhobo kufuneka sithathelwe ingqalelo.Uphando kwizinto ezintsha zokuva kunye nophando kwizicwangciso eziphuculweyo zokuyila kuya kufuneka ukuze kuphuculwe ngakumbi ukusebenza kweenzwa zegesi kunye nokujongana nemingeni eseleyo kwixesha elizayo.Ukulungiswa kokulawulwa kweempawu zenzwa, kuyimfuneko ukwakha ngokucwangcisiweyo ubudlelwane phakathi kwendlela yokwenziwa kwezinto zenzwa kunye nomsebenzi we-heteronanostructures.Ukongeza, uphononongo lokuphendula komphezulu kunye notshintsho kwi-heterointerfaces kusetyenziswa iindlela zale mihla zokubonisa iimpawu kunokunceda ukucacisa iindlela zokubona kwabo kunye nokubonelela ngeengcebiso zophuhliso lwezinzwa ezisekelwe kwizinto ezenziwe nge-heteronanostructured.Okokugqibela, uphononongo lweendlela zanamhlanje zokwenziwa kwenzwa kunokuvumela ukwenziwa kwezinzwa zegesi ezincinci kwinqanaba le-wafer kwizicelo zabo zemizi-mveliso.
Genzel, NN et al.Uphononongo olude lwamanqanaba e-nitrogen dioxide yangaphakathi kunye neempawu zokuphefumla kubantwana abane-asthma kwimimandla yasezidolophini.Ebumelwaneni.Imbono yezempilo.116, 1428-1432 (2008).
Ixesha lokuposa: Nov-04-2022
