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Sixela impembelelo emangalisayo ye-photovoltaic kwi-YBa2Cu3O6.96 (YBCO) ceramic phakathi kwe-50 kunye ne-300 K ebangelwa kukukhanya kwe-blue-laser, okunxulumene ngokuthe ngqo ne-superconductivity ye-YBCO kunye ne-YBCO-metallic electrode interface. Kukho ukuguquka kwe-polarity kwi-open circuit voltage i-Voc kunye ne-short circuit current Isc xa i-YBCO itshintsha ukusuka kwi-superconducting ukuya kwi-resistive state. Sibonisa ukuba kukho amandla ombane kwi-superconductor-normal metal interface, ebonelela ngamandla okwahlula ii-photo-induced electron-hole pairs. Le potential ye-interface iqondisa ukusuka kwi-YBCO ukuya kwi-metal electrode xa i-YBCO i-superconducting kwaye itshintshela kwicala elichaseneyo xa i-YBCO ingaba yi-superconducting. Imvelaphi ye-potential inokunxulunyaniswa ngokulula ne-proximity ye-proximity kwi-metal-superconductor interface xa i-YBCO i-superconducting kwaye ixabiso layo liqikelelwa ukuba li-~10–8 mV kwi-50 K nge-laser intensity ye-502 mW/cm2. Ukudibana kwezinto ze-p-type YBCO kwimeko eqhelekileyo nezinto ze-n-type Ag-paste yenza i-quasi-pn junction enoxanduva lokuziphatha kwe-photovoltaic kweeseramikhi ze-YBCO kumaqondo obushushu aphezulu. Iziphumo zethu zinokuvula indlela yokusetyenziswa okutsha kwezixhobo ze-photon-electronic kwaye zikhanyise ngakumbi ngesiphumo sokusondela kwi-interface ye-superconductor-metal.
I-voltage ebangelwa yifoto kwii-superconductors zobushushu obuphezulu ibikwe ekuqaleni kweminyaka yoo-1990 kwaye iphandwe kakhulu ukususela ngoko, kodwa uhlobo lwayo kunye nendlela esebenza ngayo azikalungiswa1,2,3,4,5. Iifilimu ezincinci ze-YBa2Cu3O7-δ (YBCO)6,7,8, ngokukodwa, zifundwa ngokunzulu ngendlela yeseli ye-photovoltaic (PV) ngenxa yomahluko wayo wamandla ohlengahlengiswayo9,10,11,12,13. Nangona kunjalo, ukumelana okuphezulu kwe-substrate kusoloko kukhokelela ekusebenzeni okuphantsi kokuguqulwa kwesixhobo kwaye kufihla iipropati eziphambili ze-PV ze-YBCO8. Apha sixela isiphumo esimangalisayo se-photovoltaic esibangelwa kukukhanya kwe-blue-laser (λ = 450 nm) kwi-YBa2Cu3O6.96 (YBCO) ceramic phakathi kwe-50 kunye ne-300 K (Tc ~ 90 K). Sibonisa ukuba isiphumo se-PV sinxulumene ngokuthe ngqo ne-superconductivity ye-YBCO kunye nohlobo lwe-interface ye-electrode ye-YBCO-metallic. Kukho ukuguquka kwe-polarity kwi-open circuit voltage iVoc kunye ne-short circuit current isc xa i-YBCO idlula kwi-superconducting phase ukuya kwi-resistive state. Kucetyiswa ukuba kukho amandla ombane kwi-superconductor-normal metal interface, enika amandla okwahlula ii-photo-induced electron-hole pairs. Le interface potential iqondisa ukusuka kwi-YBCO ukuya kwi-metal electrode xa i-YBCO i-superconducting kwaye itshintshela kwicala elichaseneyo xa isampuli ingabi yi-superconducting. Imvelaphi ye-potential inokunxulunyaniswa ngokwemvelo ne-proximity effect14,15,16,17 kwi-metal-superconductor interface xa i-YBCO i-superconducting kwaye ixabiso layo liqikelelwa ukuba yi-~10−8 mV kwi-50 K nge-laser intensity ye-502 mW/cm2. Udibaniso lwe-p-type material YBCO kwi-normal condition kunye ne-n-type material Ag-paste yenza, mhlawumbi, i-quasi-pn junction enoxanduva lokuziphatha kwe-PV ye-YBCO ceramics kumaqondo obushushu aphezulu. Izinto esizibonileyo zikhanyise ngakumbi ngemvelaphi yesiphumo se-PV kwi-YBCO ceramics ezisebenzisa ubushushu obuphezulu kwaye zivula indlela yokusetyenziswa kwayo kwizixhobo ze-optoelectronic ezifana ne-fast passive light detector njl.njl.
Umfanekiso 1a–c ubonisa ukuba iimpawu ze-IV zesampulu ye-ceramic ye-YBCO kwi-50 K. Ngaphandle kokukhanya okukhanyayo, i-voltage kwisampulu ihlala kwi-zero kunye notshintsho lwamandla, njengoko kunokulindeleka kwizinto eziqhuba i-superconducting. Isiphumo esicacileyo se-photovoltaic sivela xa umqadi we-laser ujoliswe kwi-cathode (Umfanekiso 1a): ii-IV curves ezihambelana ne-I-axis zihamba ziyehla ngokunyusa amandla e-laser. Kuyacaca ukuba kukho i-negative photo-induced voltage nangona ingenayo nayiphi na i-current (edla ngokubizwa ngokuba yi-open circuit voltage Voc). I-zero slope ye-IV curve ibonisa ukuba isampulu isaqhuba i-superconducting phantsi kokukhanya kwe-laser.
(a–c) kunye ne-300 K (e–g). Amaxabiso e-V(I) afunyenwe ngokutshayela umbane ukusuka kwi-−10 mA ukuya kwi-+10 mA kwi-vacuum. Inxalenye yedatha yovavanyo kuphela evezwayo ukuze kucace. a, Iimpawu ze-current-voltage ze-YBCO ezilinganiswe nge-laser spot ebekwe kwi-cathode (i). Zonke ii-IV curves ziyimigca ethe tye ethe tye ebonisa ukuba isampuli isaqhuba i-superconducting nge-laser irradiation. I-curve ihamba phantsi ngokuqina kwe-laser okwandayo, okubonisa ukuba kukho amandla angalunganga (iVoc) phakathi kwee-voltage leads ezimbini nokuba kukho i-zero current. Ii-IV curves azitshintshi xa i-laser ijoliswe embindini wesampuli kwi-ether 50 K (b) okanye kwi-300 K (f). Umgca othe tye uhamba phezulu njengoko i-anode ikhanyiswa (c). Imodeli yeskematiki ye-metal-superconductor junction kwi-50 K iboniswe kwi-d. Iimpawu ze-current-voltage zemeko eqhelekileyo ye-YBCO kwi-300 K elinganiswe nge-laser beam ekhombe kwi-cathode kunye ne-anode zinikwe kwi-e kunye ne-g ngokulandelelanayo. Ngokwahlukileyo kwiziphumo kwi-50 K, i-non-zero slope yemigca ethe tye ibonisa ukuba i-YBCO ikwimeko eqhelekileyo; amaxabiso e-Voc ayahluka ngokukhanya okunamandla kwicala elichaseneyo, okubonisa indlela eyahlukileyo yokwahlula itshaja. Ulwakhiwo olunokwenzeka lwe-interface kwi-300 K luboniswe kwi-hj Umfanekiso wokwenyani wesampulu eneeledi.
I-YBCO etyebileyo kwi-oksijini kwimeko ye-superconducting inokufunxa phantse i-spectrum epheleleyo yokukhanya kwelanga ngenxa yesithuba sayo samandla esincinci kakhulu (Umz. 9,10), ngaloo ndlela kudala ii-electron-hole pairs (e-h). Ukuvelisa i-open circuit voltage Voc ngokufunxa ii-photons, kuyimfuneko ukwahlula ii-eh pairs ezenziwe nge-photo ngaphambi kokuba kwenzeke i-recombination18. I-negative Voc, xa ithelekiswa ne-cathode kunye ne-anode njengoko kubonisiwe kuMfanekiso 1i, ibonisa ukuba kukho amandla ombane kuyo yonke indawo ye-metal-superconductor, ehambisa ii-electron kwi-anode kunye nemingxuma kwi-cathode. Ukuba kunjalo, kufuneka kubekho i-potential pointing ukusuka kwi-superconductor ukuya kwi-metal electrode kwi-anode. Ngenxa yoko, i-Voc entle iya kufunyanwa ukuba indawo yesampulu kufutshane ne-anode ikhanyisiwe. Ngaphezu koko, akufuneki kubekho ii-voltages ezibangelwa yi-photo xa indawo ye-laser ikhomba kwiindawo ezikude nee-electrodes. Ngokuqinisekileyo kunjalo njengoko kunokubonwa kuMfanekiso 1b,c!.
Xa indawo yokukhanya isuka kwi-electrode ye-cathode iye embindini wesampuli (malunga ne-1.25 mm ukusuka kwiindawo ezidityanisiweyo), akukho tshintsho lwee-IV curves kwaye akukho Voc inokubonwa ngokunyusa i-laser intensity ukuya kwixabiso eliphezulu elifumanekayo (Umzobo 1b). Ngokwemvelo, esi siphumo sinokubangelwa bubomi obulinganiselweyo bezithuthi ezibangelwa yifoto kunye nokungabikho kwamandla okwahlula kwisampuli. Ii-electron-hole pairs zinokwenziwa nanini na xa isampuli ikhanyiswa, kodwa uninzi lwee-e-h pairs ziya kutshatyalaliswa kwaye akukho siphumo se-photovoltaic esibonwayo ukuba indawo ye-laser iwela kwiindawo ezikude nayo nayiphi na i-electrodes. Ukuhambisa indawo ye-laser kwii-electrodes ze-anode, ii-IV curves ezihambelana ne-I-axis ziya phezulu ngokunyusa i-laser intensity (Umzobo 1c). Intsimi yombane efanayo eyakhelwe ngaphakathi ikhona kwi-metal-superconductor junction kwi-anode. Nangona kunjalo, i-metallic electrode iqhagamshela kwi-positive lead yenkqubo yovavanyo ngeli xesha. Imingxunya eveliswa yi-laser ityhalelwa kwi-anode lead kwaye ngaloo ndlela i-Voc iyabonakala. Iziphumo ezivezwe apha zibonelela ngobungqina obuqinileyo bokuba kukho i-interface potential ekhomba ukusuka kwi-superconductor ukuya kwi-electrode yesinyithi.
Isiphumo se-photovoltaic kwi-ceramics ze-YBa2Cu3O6.96 kwi-300 K siboniswe kwiFig. 1e–g. Ngaphandle kokukhanya, i-IV curve yesampuli ngumgca othe tye onqumla imvelaphi. Lo mgca othe tye uhamba uye phezulu uhambelana nowokuqala kunye nokwanda kokuqina kwe-laser okukhanyiswa kwi-cathode leads (Fig. 1e). Kukho iimeko ezimbini ezithintelayo ezinomdla kwisixhobo se-photovoltaic. Imeko ye-short-circuit yenzeka xa i-V = 0. Umbane kweli tyala ubizwa ngokuba yi-short circuit current (Isc). Ityala lesibini elithintelayo yimeko ye-open-circuit (Voc) eyenzeka xa i-R→∞ okanye umbane ungo-zero. Umfanekiso 1e ubonisa ngokucacileyo ukuba i-Voc ilungile kwaye iyanda ngokukhanya okwandayo, ngokuchaseneyo nesiphumo esifunyenwe kwi-50 K; ngelixa i-Isc engalunganga ibonwa inyuka ngobukhulu ngokukhanya kokukhanya, ukuziphatha okuqhelekileyo kweeseli zelanga eziqhelekileyo.
Ngokufanayo, xa umqadi welaser ukhombe kwiindawo ezikude nee-electrodes, i-V(I) curve ayixhomekekanga kubunzulu belaser kwaye akukho siphumo se-photovoltaic esibonakalayo (Umzobo 1f). Ngokufana nomlinganiselo kwi-50 K, ii-IV curves ziya kwicala elichaseneyo njengoko i-anode electrode ikhanyiswe (Umzobo 1g). Zonke ezi ziphumo zifunyenwe kule nkqubo ye-YBCO-Ag paste kwi-300 K ene-laser ekhanyiswe kwiindawo ezahlukeneyo zesampuli ziyahambelana nekhono lojongano elichaseneyo nelibonwe kwi-50 K.
Uninzi lwee-elektroni zihlangana kwii-Cooper pairs kwi-superconducting YBCO ngaphantsi kobushushu bayo bokutshintsha i-Tc. Ngelixa zikwi-electrode yesinyithi, zonke ii-elektroni zihlala zikwimo enye. Kukho i-density gradient enkulu yee-elektroni enye kunye nee-Cooper pairs kufutshane ne-interface ye-metal-superconductor. Ii-elektroni ezininzi ezithwala i-singular kwi-metallic material ziya kusasazeka ziye kummandla we-superconductor, ngelixa ii-Cooper-pairs ezininzi ezithwala i-singular kwingingqi ye-YBCO ziya kusasazeka ziye kummandla wesinyithi. Njengoko ii-Cooper zithwele ii-charges ezingaphezulu kwaye zinokuhamba okukhulu kunee-singular electrons zisasazeka kwi-YBCO ziye kummandla wesinyithi, ii-athomu ezitshajiswe kakuhle ziyashiywa ngasemva, nto leyo ebangela intsimi yombane kwindawo ye-space charge. Icala lale ntsimi yombane liboniswe kumzobo weskimu Umfanekiso 1d. Ukukhanya kwe-photon yesiganeko kufutshane nendawo ye-space charge kunokudala ii-eh pairs eziya kwahlulwa kwaye zitshayelwe zivelise i-photocurrent kwicala elichaseneyo. Kwakamsinya nje ukuba ii-elektroni ziphume kwintsimi yombane eyakhelwe ngaphakathi, ziyancitshiswa zibe ngababini kwaye zigeleze ziye kwenye i-electrode ngaphandle kokumelana. Kule meko, iVoc ichasene ne-polarity esethiweyo kwaye ibonisa ixabiso elibi xa umqadi welaser ukhomba kwindawo ejikeleze i-electrode engalunganga. Ukusuka kwixabiso leVoc, amandla angaphaya kojongano angaqikelelwa: umgama phakathi kwee-voltage leads ezimbini d yi ~5 × 10−3 m, ubukhulu bojongano lwe-metal-superconductor, di, kufuneka bube ngokulandelelana okufanayo nobude bokuhambelana kwe-YBCO superconductor (~1 nm)19,20, thabatha ixabiso leVoc = 0.03 mV, ii-Vms ezinokubakho kujongano lwe-metal-superconductor zivavanywa zibe yi ~10−11 V kwi-50 K kunye namandla e-laser angama-502 mW/cm2, kusetyenziswa i-equation,
Sifuna ukugxininisa apha ukuba i-voltage ebangelwa yifoto ayinakuchazwa ngesiphumo sobushushu befoto. Kuye kwamiselwa ngovavanyo ukuba i-coefficient yeSeebeck ye-superconductor YBCO yi-Ss = 021. I-coefficient yeSeebeck yeentambo ze-copper lead ikuluhlu lwe-SCu = 0.34–1.15 μV/K3. Ubushushu bentambo yobhedu kwindawo yelaser bunokunyuka ngenani elincinci le-0.06 K kunye nobukhulu be-laser obufumaneka kwi-50 K. Oku kunokuvelisa amandla e-thermoelectric angama-6.9 × 10−8 V angama-odolo amathathu amancinci kune-Voc efunyenwe kwiFig 1 (a). Kuyacaca ukuba isiphumo se-thermoelectric sincinci kakhulu ukuchaza iziphumo zovavanyo. Enyanisweni, utshintsho lobushushu olubangelwa yi-laser irradiation luya kuphela ngaphantsi komzuzu omnye ukuze igalelo elivela kwisiphumo sobushushu lingahoywa ngokukhuselekileyo.
Esi siphumo se-photovoltaic se-YBCO kubushushu begumbi sityhila ukuba kukho indlela eyahlukileyo yokwahlula itshaja apha. I-Superconducting YBCO kwimeko eqhelekileyo yimpahla ye-p-type enemingxuma njenge-charge carrier22,23, ngelixa i-Ag-paste yentsimbi ineempawu zezinto ze-n-type. Njengee-pn junctions, ukusasazeka kwee-electron kwi-silver paste kunye nemingxuma kwi-YBCO ceramic kuya kwenza intsimi yombane yangaphakathi ekhomba kwi-YBCO ceramic kwi-interface (Umzobo 1h). Yile ntsimi yangaphakathi enika amandla okwahlula kwaye ikhokelele kwi-Voc entle kunye ne-negative Isc yenkqubo ye-YBCO-Ag paste kubushushu begumbi, njengoko kubonisiwe kwi-Fig. 1e. Ngaphandle koko, i-Ag-YBCO inokwenza i-p-type Schottky junction ekwakhokelela kwi-interface potential ene-polarity efanayo naleyo ikwimodeli eboniswe apha ngasentla24.
Ukuphanda inkqubo yokuvela eneenkcukacha zeempawu ze-photovoltaic ngexesha lotshintsho lwe-superconducting ye-YBCO, ii-IV curves zesampuli kwi-80 K zilinganiswe ngamandla e-laser akhethiweyo akhanyisa kwi-cathode electrode (Umzobo 2). Ngaphandle kokukhanyiswa nge-laser, i-voltage kwisampuli igcina ikwi-zero nokuba ingakanani na i-current, nto leyo ebonisa imeko ye-superconducting yesampuli kwi-80 K (Umzobo 2a). Ngokufanayo nedatha efunyenwe kwi-50 K, ii-IV curves ezihambelana ne-I-axis zihamba ziyehla ngokwandisa i-laser intensity de kufikelelwe kwixabiso elibalulekileyo i-Pc. Ngaphezulu kwale intensity ye-laser intensity (Pc), i-superconductor idlula kwi-transition ukusuka kwi-superconducting phase ukuya kwi-resistive phase; i-voltage iqala ukunyuka nge-current ngenxa yokubonakala kwe-resistance kwi-superconductor. Ngenxa yoko, i-IV curve iqala ukudibana ne-I-axis kunye ne-V-axis ekhokelela kwi-Voc engalunganga kunye ne-Isc entle ekuqaleni. Ngoku isampuli ibonakala ikwimeko ekhethekileyo apho i-polarity ye-Voc kunye ne-Isc ivakalelwa kakhulu kubunzulu bokukhanya; Ngokwanda okuncinci kakhulu kokukhanya, i-Isc iguqulwa ukusuka kwi-positive ukuya kwi-negative kwaye i-Voc ukusuka kwi-negative ukuya kwi-positive value, idlula imvelaphi (uvakalelo oluphezulu lweempawu ze-photovoltaic, ngakumbi ixabiso le-Isc, ukuya ekukhanyeni kokukhanya lunokubonwa ngokucacileyo kwiFig. 2b). Kwi-laser intensity ephezulu ekhoyo, ii-IV curves zifuna ukuba zihambelane, nto leyo ebonisa imeko eqhelekileyo yesampulu ye-YBCO.
Iziko le-laser spot libekwe ngeenxa zonke kwi-cathode electrodes (jonga uMzobo 1i). a, ii-IV curves ze-YBCO ezikhanyiswa ngamandla ahlukeneyo e-laser. b (phezulu), Ukuxhomekeka kobunzulu be-Laser kwi-open circuit voltage iVoc kunye ne-short circuit current Isc. Amaxabiso e-Isc awafumaneki kubunzulu bokukhanya obuphantsi (< 110 mW/cm2) kuba ii-IV curves zihambelana ne-I-axis xa isampuli ikwimeko ye-superconducting. b (ezantsi), ukumelana kokwahluka njengomsebenzi wobunzulu be-laser.
Ukuxhomekeka kwe-laser intensity yeVoc kunye ne-Isc kwi-80 K kuboniswe kwiFig. 2b (phezulu). Iimpawu ze-photovoltaic zingaxoxwa ngazo kwiindawo ezintathu zokukhanya. Ummandla wokuqala uphakathi kwe-0 kunye ne-Pc, apho i-YBCO iqhuba i-superconducting, i-Voc i-negative kwaye iyancipha (ixabiso elipheleleyo liyakhula) ngokukhanya kwaye ifikelela ubuncinci kwi-Pc. Ummandla wesibini usuka kwi-Pc uye kwenye intensity ebalulekileyo ye-P0, apho i-Voc iyanda ngelixa i-Isc iyancipha ngokukhanya okwandayo kwaye zombini zifikelela kwi-zero kwi-P0. Ummandla wesithathu ungaphezulu kwe-P0 de kufikelelwe kwimeko eqhelekileyo ye-YBCO. Nangona zombini i-Voc kunye ne-Isc zahluka ngokukhanya ngendlela efanayo nakwengingqi yesi-2, zine-polarity echaseneyo ngaphezu kwe-critical intensity P0. Ukubaluleka kwe-P0 kukuba akukho siphumo se-photovoltaic kwaye indlela yokwahlula itshaja iyatshintsha ngokwemigangatho kweli nqanaba lithile. Isampulu ye-YBCO ayiba yi-superconducting kolu luhlu lokukhanya kodwa imeko eqhelekileyo ayikafikelelwa.
Ngokucacileyo, iimpawu ze-photovoltaic zenkqubo zinxulumene ngokusondeleyo ne-superconductivity ye-YBCO kunye notshintsho lwayo lwe-superconducting. Ukumelana komahluko, i-dV/dI, ye-YBCO kuboniswe kwiFig. 2b (ezantsi) njengomsebenzi we-laser intensity. Njengoko kukhankanyiwe ngaphambili, amandla ombane okwakhelwa ngaphakathi kwi-interface ngenxa yamanqaku okusasazwa kwe-Cooper pair ukusuka kwi-superconductor ukuya kwisinyithi. Ngokufanayo naleyo ibonwe kwi-50 K, isiphumo se-photovoltaic siyandiswa ngokunyusa amandla e-laser ukusuka kwi-0 ukuya kwi-Pc. Xa i-laser inamandla ifikelela kwixabiso elingaphezulu kancinci kwi-Pc, i-IV curve iqala ukuthambeka kwaye ukumelana kwesampuli kuqala ukubonakala, kodwa i-polarity ye-interface potential ayikatshintshi okwangoku. Isiphumo se-optical excitation kwi-superconductivity siphandwe kwindawo ebonakalayo okanye ekufutshane ne-IR. Ngelixa inkqubo esisiseko ikukwaphula ii-Cooper pairs kunye nokutshabalalisa i-superconductivity25,26, kwezinye iimeko utshintsho lwe-superconductivity lunokuphuculwa27,28,29, amanqanaba amatsha e-superconductivity anokubangelwa30. Ukungabikho kwe-superconductivity kwi-Pc kunokubangelwa kukwaphuka kwesibini esibangelwa yifoto. Kwinqaku le-P0, amandla kulo lonke i-interface aba zero, nto leyo ebonisa ukuba uxinano lwetshaja kumacala omabini e-interface lufikelela kwinqanaba elifanayo phantsi kolu xinzelelo lokukhanya. Ukwanda ngakumbi kobunzulu be-laser kubangela ukuba ii-Cooper pairs ezininzi zitshatyalaliswe kwaye i-YBCO iguqulwa kancinci kancinci ibe yinto ye-p-type. Endaweni yokusasazwa kwe-electron kunye ne-Cooper pair, uphawu lwe-interface ngoku lumiselwa kukusasazwa kwe-electron kunye ne-hole okukhokelela ekuguqulweni kwe-polarity yentsimi yombane kwi-interface kwaye ngenxa yoko i-Voc entle (thelekisa uMfanekiso 1d, h). Kwi-laser intensity ephezulu kakhulu, ukumelana kokwahluka kwe-YBCO kugcwala kwixabiso elihambelana nemeko eqhelekileyo kwaye zombini i-Voc kunye ne-Isc zivame ukwahluka ngokuthe ngqo kunye nobunzulu be-laser (Umzobo 2b). Oku kuqaphela kubonisa ukuba i-laser irradiation kwi-normal state YBCO ayisayi kutshintsha i-resistivity yayo kunye nophawu lwe-superconductor-metal interface kodwa yonyusa kuphela uxinzelelo lwee-electron-hole pairs.
Ukuze kuphandwe impembelelo yobushushu kwiipropati ze-photovoltaic, inkqubo ye-metal-superconductor inikwe i-radiation kwi-cathode nge-laser eluhlaza okwesibhakabhaka enamandla angama-502 mW/cm2. Ii-IV curves ezifunyenwe kumaqondo obushushu akhethiweyo phakathi kwama-50 nama-300 K zinikwe kwiFig. 3a. I-open circuit voltage i-Voc, i-short circuit current i-Isc kunye ne-differential resistance zinokufunyanwa kwezi curves ze-IV kwaye ziboniswe kwiFig. 3b. Ngaphandle kokukhanya okukhanyayo, zonke ii-IV curves ezilinganiswe kumaqondo obushushu ahlukeneyo zidlula imvelaphi njengoko bekulindelwe (i-inset yeFig. 3a). Iimpawu ze-IV zitshintsha kakhulu ngobushushu obukhulayo xa inkqubo ikhanyiswa yi-laser beam enamandla (502 mW/cm2). Kumaqondo obushushu aphantsi ii-IV curves ziyimigca ethe tye ehambelana ne-I-axis enexabiso elibi le-Voc. Le curve inyuka ngobushushu obukhulayo kwaye kancinci kancinci ijika ibe ngumgca one-nonzero slope kwi-critical temperature Tcp (Fig. 3a (phezulu)). Kubonakala ngathi zonke ii-IV characteristic curves zijikeleza inqaku kwi-quadrant yesithathu. I-Voc iyanda ukusuka kwixabiso elibi ukuya kwelihle ngelixa i-Isc iyancipha ukusuka kwixabiso elibi ukuya kwelihle. Ngaphezulu kobushushu bokuqala bokutshintsha kwe-superconducting Tc ye-YBCO, i-IV curve itshintsha ngokwahlukileyo ngobushushu (ezantsi koMfanekiso 3a). Okokuqala, iziko lokujikeleza lee-IV curves lihamba liye kwi-quadrant yokuqala. Okwesibini, i-Voc iyaqhubeka nokwehla kwaye i-Isc iyanda ngobushushu obukhulayo (phezulu koMfanekiso 3b). Okwesithathu, ukuthambeka kwee-IV curves kuyanda ngokuthe ngqo ngobushushu okubangela ukuba i-YBCO ibe ne-coefficient yokumelana nobushushu (ezantsi koMfanekiso 3b).
Ukuxhomekeka kobushushu kwiimpawu ze-photovoltaic kwinkqubo ye-YBCO-Ag paste phantsi kokukhanya kwelaser kwe-502 mW/cm2.
Iziko le-laser spot libekwe lijikeleze ii-electrodes ze-cathode (jonga uMzobo 1i). a, ii-IV curves ezifunyenwe ukusuka kwi-50 ukuya kwi-90 K (phezulu) kunye ukusuka kwi-100 ukuya kwi-300 K (ezantsi) kunye nokunyuka kobushushu obuyi-5 K kunye ne-20 K, ngokulandelanayo. I-Inset a ibonisa iimpawu ze-IV kumaqondo obushushu ahlukeneyo kumnyama. Zonke ii-curves ziwela i-origin point. b, i-open circuit voltage i-Voc kunye ne-short circuit current i-Isc (ephezulu) kunye ne-differential resistance, i-dV/dI, ye-YBCO (ezantsi) njengomsebenzi wobushushu. I-zero resistance superconducting transition temperature i-Tcp ayinikwanga kuba ikufutshane kakhulu ne-Tc0.
Amaqondo obushushu amathathu abalulekileyo anokubonwa kwiFig. 3b: I-Tcp, ngaphezulu apho i-YBCO ingabi yi-superconducting; i-Tc0, apho zombini i-Voc kunye ne-Isc ziba yi-zero kunye ne-Tc, ubushushu bokuqala bokutshintsha kwe-superconducting ye-YBCO ngaphandle kokukhanya kwe-laser. Ngaphantsi kwe-Tcp ~ 55 K, i-YBCO ekhanyisiweyo ye-laser ikwimeko yokuqhuba ngamandla aphezulu kunye noxinzelelo oluphezulu lwee-Cooper pairs. Isiphumo sokukhanya kwe-laser kukunciphisa ubushushu bokutshintsha kwe-superconducting ye-zero resistance ukusuka kwi-89 K ukuya kwi-~55 K (ezantsi kweFig. 3b) ngokunciphisa uxinzelelo lwe-Cooper pair ukongeza ekuveliseni i-voltage ye-photovoltaic kunye ne-current. Ubushushu obandayo bukwaphula ii-Cooper pairs ezikhokelela kwi-potential ephantsi kwi-interface. Ngenxa yoko, ixabiso elipheleleyo le-Voc liya kuba lincinci, nangona amandla afanayo okukhanyisa kwe-laser asetyenziswa. I-interface potential iya kuba ncinci ngakumbi ngokunyuka kobushushu kwaye ifikelele kwi-zero kwi-Tc0. Akukho siphumo se-photovoltaic kule ndawo ikhethekileyo kuba akukho ntsimi yangaphakathi yokwahlula ii-photo-induced electron-hole pairs. Ukuguqulwa kwe-polarity ye-potential kwenzeka ngaphezulu kobu bushushu bubalulekileyo njengoko uxinano lwe-free charge kwi-Ag paste lukhulu kunolo lukwi-YBCO oluthi kancinci kancinci ludluliselwe kwi-p-type material. Apha sifuna ukugxininisa ukuba ukuguqulwa kwe-polarity ye-Voc kunye ne-Isc kwenzeka kwangoko emva kotshintsho lwe-zero resistance superconducting, nokuba yintoni na imbangela yotshintsho. Olu qwalaselo lubonisa ngokucacileyo, okokuqala, ulwalamano phakathi kwe-superconductivity kunye neziphumo ze-photovoltaic ezinxulumene ne-metal-superconductor interface potential. Uhlobo lwale potential kulo lonke i-superconductor-normal metal interface lube yinto egxininisiweyo kuphando kwiminyaka emininzi edlulileyo kodwa kukho imibuzo emininzi esalindele ukuphendulwa. Ukulinganiswa kwesiphumo se-photovoltaic kunokuba yindlela esebenzayo yokuhlola iinkcukacha (ezifana namandla ayo kunye ne-polarity njl.njl.) zale potential ibalulekileyo kwaye ngaloo ndlela ikhanyise isiphumo sokusondela kwe-superconducting yobushushu obuphezulu.
Ukwanda ngakumbi kobushushu ukusuka kwi-Tc0 ukuya kwi-Tc kukhokelela kuxinzelelo oluncinci lwee-Cooper pairs kunye nokuphuculwa kwamandla ojongano kwaye ngenxa yoko i-Voc enkulu. Kwi-Tc uxinzelelo lwe-Cooper pair luba zero kwaye amandla okwakha kwi-interface afikelela kwinqanaba eliphezulu, nto leyo ebangela i-Voc ephezulu kunye ne-Isc encinci. Ukwanda ngokukhawuleza kwe-Voc kunye ne-Isc (ixabiso elipheleleyo) kolu luhlu lobushushu kuhambelana notshintsho lwe-superconducting olunwebeka ukusuka kwi-ΔT ~ 3 K ukuya kwi-~34 K ngokukhanyiselwa nge-laser kobunzulu obuyi-502 mW/cm2 (Umzobo 3b). Kwiimeko eziqhelekileyo ezingaphezulu kwe-Tc, i-voltage yesekethe evulekileyo i-Voc iyancipha ngobushushu (phezulu koMfanekiso 3b), efana nokuziphatha okuthe ngqo kwe-Voc kwiiseli zelanga eziqhelekileyo ngokusekelwe kwi-pn junctions31,32,33. Nangona izinga lokutshintsha kwe-Voc ngobushushu (−dVoc/dT), elixhomekeke kakhulu kubunzulu be-laser, lincinci kakhulu kuneleeseli zelanga eziqhelekileyo, i-coefficient yobushushu ye-Voc kwi-YBCO-Ag junction inomyalelo ofanayo noweeseli zelanga. Ukuvuza komsinga we-pn junction yesixhobo seseli yelanga esiqhelekileyo kuyanda ngobushushu obukhulayo, nto leyo ekhokelela ekwehleni kweVoc njengoko ubushushu busanda. Ii-linear IV curves ezibonwe kule nkqubo ye-Ag-superconductor, okokuqala ngenxa ye-interface potential encinci kakhulu kwaye okwesibini uqhagamshelo olubuyela umva lwe-heterojunctions ezimbini, kwenza kube nzima ukumisela umsinga wokuvuza. Nangona kunjalo, kunokwenzeka ukuba ukuxhomekeka kobushushu obufanayo komsinga wokuvuza kunoxanduva lokuziphatha kweVoc okubonwe kuvavanyo lwethu. Ngokwenkcazo, i-Isc ngumsinga ofunekayo ukuvelisa i-voltage engalunganga yokubuyisela iVoc ukuze i-voltage iyonke ibe zero. Njengoko ubushushu busanda, iVoc iba ncinci kangangokuba kufuneka umsinga omncinci ukuvelisa i-voltage engalunganga. Ngaphezu koko, ukumelana kwe-YBCO kuyanda ngokuthe ngqo ngobushushu obungaphezulu kwe-Tc (ezantsi koMfanekiso 3b), okongeza kwixabiso elincinci le-Isc kumaqondo obushushu aphezulu.
Qaphela ukuba iziphumo ezinikwe kwiMifanekiso 2,3 zifunyanwa ngokukhanyisela nge-laser kwindawo ejikeleze ii-electrodes ze-cathode. Ukulinganisa kuphindwe kwakhona nge-laser spot ebekwe kwi-anode kwaye iimpawu ezifanayo ze-IV kunye neempawu ze-photovoltaic zibonwe ngaphandle kokuba i-polarity ye-Voc kunye ne-Isc iguqulwe kweli tyala. Zonke ezi datha zikhokelela kwindlela yokusebenza kwe-photovoltaic effect, enxulumene ngokusondeleyo ne-superconductor-metal interface.
Ngamafutshane, iimpawu ze-IV zenkqubo ye-laser irradiated superconducting YBCO-Ag paste zilinganiswe njengemisebenzi yobushushu kunye nobunzulu be-laser. Isiphumo esiphawulekayo se-photovoltaic sibonwe kuluhlu lobushushu ukusuka kwi-50 ukuya kwi-300 K. Kufunyaniswe ukuba iipropati ze-photovoltaic zihambelana kakhulu ne-superconductivity ye-YBCO ceramics. Ukuguqulwa kwe-polarity ye-Voc kunye ne-Isc kwenzeka kwangoko emva kokuguqulwa kwe-photo-induced superconducting ukuya kwi-non-superconducting. Ukuxhomekeka kobushushu be-Voc kunye ne-Isc okulinganiswe kwi-fixed laser intensity kubonisa nokuguqulwa kwe-polarity okucacileyo kubushushu obubalulekileyo ngaphezulu apho isampuli iba yi-resistive. Ngokufumana indawo ye-laser kwiindawo ezahlukeneyo zesampuli, sibonisa ukuba kukho amandla ombane kuyo yonke i-interface, enika amandla okwahlula ii-photo-induced electron-hole pairs. Le potential ye-interface iqondisa ukusuka kwi-YBCO ukuya kwi-electrode yesinyithi xa i-YBCO i-superconducting kwaye itshintshela kwicala elichaseneyo xa isampuli iba yi-non-superconducting. Imvelaphi ye-potential inokunxulunyaniswa ngokwemvelo nesiphumo sokusondela kwi-interface ye-metal-superconductor xa i-YBCO iqhuba i-superconducting kwaye kuqikelelwa ukuba yi-~10−8 mV kwi-50 K nge-laser intensity ye-502 mW/cm2. Ukudibana kwento ye-p-type YBCO kwimeko eqhelekileyo kunye nento ye-n-type Ag-paste yenza i-quasi-pn junction enoxanduva lokuziphatha kwe-photovoltaic kwee-ceramics ze-YBCO kumaqondo obushushu aphezulu. Oku kubonwe ngasentla kukhanyisa isiphumo se-PV kwi-ceramics ze-YBCO eziqhuba i-superconducting kumaqondo obushushu aphezulu kwaye kuvula indlela yezicelo ezintsha kwizixhobo ze-optoelectronic ezifana ne-fast passive light detector kunye ne-single photon detector.
Uvavanyo lwempembelelo ye-photovoltaic lwenziwe kwisampulu ye-ceramic ye-YBCO enobukhulu obuyi-0.52 mm kunye ne-8.64 × 2.26 mm2 eneemilo ezingxande kwaye yakhanyiswa yi-continuous wave blue-laser (λ = 450 nm) enobukhulu be-laser spot obuyi-1.25 mm kwi-radius. Ukusebenzisa isampulu yefilimu enobukhulu kunokuba ibe yi-thin film kusenza sikwazi ukufunda iipropati ze-photovoltaic ze-superconductor ngaphandle kokujongana nempembelelo enzima ye-substrate6,7. Ngaphezu koko, izinto ezinobuninzi zinokulungela inkqubo yayo yokulungiselela elula kunye nexabiso eliphantsi. Iintambo ze-copper lead zidibene kwisampulu ye-YBCO nge-silver paste eyenza ii-electrode ezine ezijikelezayo malunga ne-1 mm ububanzi. Umgama phakathi kwee-electrode ezimbini ze-voltage umalunga ne-5 mm. Iimpawu ze-IV zesampulu zilinganiswe kusetyenziswa i-vibration sample magnetometer (VersaLab, Quantum Design) enefestile yekristale ye-quartz. Indlela eqhelekileyo ye-four-wire yasetyenziswa ukufumana ii-IV curves. Izikhundla ezihambelanayo zee-electrode kunye ne-laser spot ziboniswe kwiFig. 1i.
Indlela yokucaphula eli nqaku: UYang, F. et al. Imvelaphi yesiphumo se-photovoltaic kwi-superconducting YBa2Cu3O6.96 ceramics. Sci. Rep. 5, 11504; doi: 10.1038/srep11504 (2015).
UChang, CL, Kleinhammes, A., Moulton, WG kunye noTestardi, LR Iivoltages ezibangelwa yilaser ezingavumelekanga kwi-YBa2Cu3O7 . Phys. Rev. B 41, 11564–11567 (1990).
UKwok, HS, Zheng, JP kunye noDong, SY Imvelaphi yesignali ye-photovoltaic engaqhelekanga kwi-Y-Ba-Cu-O. Phys. Rev. B 43, 6270–6272 (1991).
UWang, LP, uLin, uJL, uFeng, uQR kunye noWang, uGW Ukulinganiswa kwee-voltages ezibangelwa yilaser ze-superconducting Bi-Sr-Ca-Cu-O. Phys. Rev. B 46, 5773–5776 (1992).
Tate, KL, et al. Iivoltages ezibangelwa yilaser ezidlulayo kwiifilimu zobushushu begumbi zeYBa2Cu3O7-x. J. Appl. Phys. 67, 4375–4376 (1990).
UKwok, HS kunye noZheng, JP Impendulo ye-photovoltaic engaqhelekanga kwi-YBa2Cu3O7. Phys. Rev. B 46, 3692–3695 (1992).
UMuraoka, Y., Muramatsu, T., Yamaura, J. kunye noHiroi, Z. Inaliti yokuthwala umngxuma eveliswe ngefoto kwiYBa2Cu3O7−x kwisakhiwo se-oxide heterostructure. Appl. Phys. Lett. 85, 2950–2952 (2004).
Asakura, D. et al. Uphononongo lwe-photoemission lweefilimu ezincinci ze-YBa2Cu3Oy phantsi kokukhanya. Phys. Rev. Lett. 93, 247006 (2004).
UYang, F. et al. Isiphumo se-photovoltaic se-YBa2Cu3O7-δ/SrTiO3 :Nb heterojunction i-annealed kwi-oxygen eyahlukileyo yoxinzelelo oluyinxenye. Mater. Lett. 130, 51–53 (2014).
U-Aminov, BA et al. Ulwakhiwo lwe-Two-Gap kwi-Yb(Y)Ba2Cu3O7-x single crystals. J. Supercond. 7, 361–365 (1994).
Kabanov, VV, Demsar, J., Podobnik, B. kunye noMihailovic, D. Iintshukumo zokuphumla zeQuasiparticle kwii-superconductors ezinezakhiwo ezahlukeneyo ze-gap: Ithiyori kunye novavanyo kwi-YBa2Cu3O7-δ. Phys. Rev. B 59, 1497–1506 (1999).
I-Sun, JR, i-Xiong, i-CM, i-Zhang, i-YZ kunye ne-Shen, i-BG Iimpawu zokulungisa ze-YBa2Cu3O7-δ/SrTiO3 :Nb heterojunction. I-Appl. Phys. Lett. 87, 222501 (2005).
Kamarás, K., Porter, CD, Doss, MG, Herr, SL kunye noTanner, DB Ukufunxwa kwe-Excitonic kunye ne-superconductivity kwi-YBa2Cu3O7-δ. Phys. Rev. Lett. 59, 919–922 (1987).
Yu, G., Heeger, AJ kunye noStucky, G. Ukuqhuba okushukumayo okushukumayo okuhamba kancinci kwiikristale ezi-semiconducting ze-YBa2Cu3O6.3: khangela imeko yesinyithi eshukumayo kunye ne-photoinduced superconductivity. Solid State Commun. 72, 345–349 (1989).
McMillan, WL Imodeli yeTunneling yesiphumo sokusondela kwe-superconducting. Phys. Rev. 175, 537–542 (1968).
UGuéron, S. et al. Isiphumo sokusondela kwe-Superconducting esiphandwe kwisikali sobude be-mesoscopic. Phys. Rev. Lett. 77, 3025–3028 (1996).
U-Annunziata, G. kunye noManske, D. Isiphumo sokusondela kunye nee-superconductors ezingezizo eze-centrosymmetric. Phys. Rev. B 86, 17514 (2012).
Qu, FM et al. Isiphumo esinamandla sokusondela kwe-superconducting kwizakhiwo ze-Pb-Bi2Te3 hybrid. Sci. Rep. 2, 339 (2012).
I-Chapin, i-DM, i-Fuller, i-CS kunye ne-Pearson, i-GL I-photocell entsha ye-silicon pn junction yokuguqula imitha yelanga ibe ngamandla ombane. J. App. Phys. 25, 676–677 (1954).
UTomimoto, K. Imiphumo yokungcola kubude bokuhambelana kwe-superconducting kwi-Zn- okanye kwi-Ni-doped YBa2Cu3O6.9 single crystals. Phys. Rev. B 60, 114–117 (1999).
U-Ando, Y. kunye noSegawa, K. Ukumelana nemagneto kweekristale ezi-Untwinned YBa2Cu3Oy ezi-single kwiindidi ezahlukeneyo ze-doping: ukuxhomekeka okungaqhelekanga kwe-hole-doping kubude bokuhambelana. Phys. Rev. Lett. 88, 167005 (2002).
UObertelli, SD kunye noCooper, JR Iinkqubo kumandla ombane we-thermoelectric we-high-T, ii-oxides. Phys. Rev. B 46, 14928–14931, (1992).
USugai, S. et al. Utshintsho loxinzelelo oluxhomekeke kwi-carrier-density lwe-coherent peak kunye ne-LO phonon mode kwii-superconductors ze-p-type high-Tc. Phys. Rev. B 68, 184504 (2003).
UNojima, T. et al. Ukunciphisa imingxunya kunye nokuqokelelwa kwee-electron kwiifilimu ezincinci ze-YBa2Cu3Oy kusetyenziswa indlela ye-electrochemical: Ubungqina bemeko yesinyithi yohlobo lwe-n. Phys. Rev. B 84, 020502 (2011).
Tung, RT Ifiziksi kunye nekhemistri yokuphakama kwesithintelo seSchottky. Appl. Phys. Lett. 1, 011304 (2014).
USai-Halasz, GA, Chi, CC, Denenstein, A. kunye noLangenberg, DN Iziphumo zoKwahlulwa kweDynamic External Pair kwiifilimu zeSuperconducting. Phys. Rev. Lett. 33, 215–219 (1974).
UNieva, G. et al. Ukuphuculwa kwe-superconductivity ebangelwa yifoto. Appl. Phys. Lett. 60, 2159–2161 (1992).
UKudinov, VI et al. Ukuqhubekeka kokuqhuba i-photoconductivity kwiifilimu ze-YBa2Cu3O6+x njengendlela yokuqhuba i-photodoping ukuya kwizigaba zesinyithi kunye ne-superconducting. Phys. Rev. B 14, 9017–9028 (1993).
UMankowsky, R. et al. Iintshukumo ze-lattice ezingezizo ezilandelelanayo njengesiseko sokuphucula i-superconductivity kwi-YBa2Cu3O6.5. I-Nature 516, 71–74 (2014).
UFausti, D. et al. Ukukhanya okubangelwa yi-superconductivity kwi-cuprate enemigca. ISayensi 331, 189–191 (2011).
U-El-Adawi, MK kunye no-Al-Nuaim, IA Ukuxhomekeka kobushushu be-VOC kwiseli yelanga ngokunxulumene nokusebenza kwayo ngendlela entsha. Ukususa ityuwa emanzini 209, 91–96 (2007).
UVernon, SM kunye noAnderson, WA Iziphumo zobushushu kwiiseli zelanga zeSchottky-barrier silicon. Appl. Phys. Lett. 26, 707 (1975).
Katz, EA, Faiman, D. kunye noTuladhar, SM Ukuxhomekeka kobushushu kwiiparamitha zesixhobo se-photovoltaic seeseli zelanga ze-polymer-fullerene phantsi kweemeko zokusebenza. J. Appl. Phys. 90, 5343–5350 (2002).
Lo msebenzi uxhaswe yiNational Natural Science Foundation yaseTshayina (Grant No. 60571063), iiProjekthi zoPhando oluSisiseko zePhondo laseHenan, eTshayina (Grant No. 122300410231).
UFY wabhala umbhalo wephepha waza uMYH walungisa isampulu yeseramikhi yeYBCO. UFY kunye noMYH benze uvavanyo baza bahlalutya iziphumo. I-FGC yakhokela iprojekthi kunye nokuchazwa kwedatha ngokwesayensi. Bonke ababhali baphonononge umbhalo-ngqangi.
Lo msebenzi unelayisenisi phantsi kweLayisensi yeHlabathi yeCreative Commons Attribution 4.0. Imifanekiso okanye ezinye izinto zomntu wesithathu kweli nqaku zifakiwe kwilayisensi yeCreative Commons yenqaku, ngaphandle kokuba kuboniswe ngenye indlela kumgca wetyala; ukuba izinto azifakwanga phantsi kwelayisensi yeCreative Commons, abasebenzisi kuya kufuneka bafumane imvume kumnini welayisenisi ukuze bavelise ezo zinto. Ukujonga ikopi yale layisenisi, ndwendwela i-http://creativecommons.org/licenses/by/4.0/
UYang, F., uHan, uM. kunye noChang, F. Imvelaphi yempembelelo ye-photovoltaic kwi-superconducting YBa2Cu3O6.96 ceramics. I-Sci Rep 5, 11504 (2015). https://doi.org/10.1038/srep11504
Ngokuthumela uluvo uyavuma ukuthobela iMigqaliselo yethu kunye neMigaqo yoLuntu. Ukuba ufumana into exhaphazayo okanye engahambelani nemigaqo okanye izikhokelo zethu nceda uyiphawule njengengafanelekanga.
Ixesha lokuthumela: Epreli-22-2020