High-Sheet-Resistance Emitters a Samar da Jama'a: Ina Ainihin Matsalar Take?
Teburin Abubuwan Ciki
Gabatarwar Samfur
Kowa a duniyar PV yana ɗauka a matsayin abin da aka sani: ƙara juriyar fitar da wutar lantarki (Rsheet) yana siyan muku Voc mafi girma, amma kuna biya ta hanyar rushewar fill factor. Don haka tambaya ta farko tana da sauƙi. Shin juriyar fitar da wutar lantarki mai yawa ta karya FF a wannan karon?
Dubi akwatunan da ke cikin hotuna a zuwa d. Bayanan sun ɗan yi kama da rashin fahimta.
High-Rsheet single poly-Si versus low-Rsheet single poly-Si: Jsc barely moves, ΔJsc is close to 0. Voc ticks up a little. And FF, instead of dropping, actually creeps up.
High-Rsheet double poly-Si is the full package. Against the low-Rsheet single poly-Si baseline, Jsc gains about 0.12 mA/cm², Voc gains about 2 mV, and FF is dragged up by roughly 0.4%.
The takeaway: the high-sheet-resistance emitter did not bring the transport penalty everyone feared. Through structural optimization, it lifted the whole set of electrical parameters instead.
Ma'aunin Fasaha
From "dead layer" to fine grid: the precision surgery
Figures e and f reveal the physics behind it.
First, kill the dead layer and double the lifetime. The ECV (electrochemical capacitance-voltage) profile in figure e shows that the surface boron concentration of the high-Rsheet emitter (red curve) sits well below the low-Rsheet one (blue curve). That means the surface "dead layer", the lattice-damaged region caused by heavy doping, gets thinner.
Wannan yana bayyana a cikin tsawon rayuwar mai ɗaukar kaya mara inganci a hoto f. Samfurin low-Rsheet ya kai 0.70 ms kawai a matakin allura na 10^15 cm^-3, yayin da samfurin high-Rsheet ya tashi kai tsaye zuwa 1.12 ms. Tsawon rayuwar mai ɗaukar kaya yana jawo ƙarancin yawan halin yanzu na sake haɗuwa J0 (duba hoto g), wanda ke ba da tushe mai ƙarfi ga ribar Voc.
| Parameter | Low-Rsheet emitter | High-Rsheet emitter |
|---|---|---|
| Tsawon rayuwar mai ɗaukar kaya (a 10^15 cm^-3) | 0.70 ms | 1.12 ms |
| Nisa tsakanin layukan grid | 1120 μm | 825 μm |
| Faɗin layin grid | 20 μm | 10 μm |
| J0 (poly-Si biyu) | mafi girma | ~5 fA/cm² |
| Ƙarfin tuntuɓar ρc (poly-Si biyu) | — | ~2-3 mΩ·cm² |
Babban juriyar takardar shi kaɗai bai isa ba, har yanzu dole ne ku gyara jigilar gefe. Kwatanta hotunan micrographs a hoto i. Mai ƙarancin-R emitter yana da grid pitch na 1120 μm da faɗin layi na 20 μm. Mai high-R emitter yana ƙara matse pitch zuwa 825 μm kuma yana rage faɗin layi zuwa 10 μm. Wannan shi ne ainihin sake fasalin grid: tunda juriyar emitter ta tashi, sanya grid ya zama mai yawa kuma mai laushi don ƙara hanyoyin gudanarwa, yayin da yatsu masu sirara ke yanke yankin inuwa. Wannan ƙirar mai laushi ba kawai tana soke asarar daga babban juriyar takardar ba, har ma tana inganta kama haske.
Fa'idodin Fasaha
Zurfin musayar ra'ayi tsakanin sigogin lantarki
Hoto g da h suna rufe sigogi biyu da injiniyan layi ya fi damuwa da su.
Yawan halin yanzu na sake haɗuwa (J0): high-Rsheet double poly-Si (digogi ja) yana da mafi ƙarancin J0, kusan 5 fA/cm², ƙasa da sauran rukunoni. Wannan yana nuna cewa tsarin double poly-Si yana toshe yaduwar ƙazantar ƙarfe yadda ya kamata kuma yana kare kariyar haɗin fuska.
Ƙarfin tuntuɓar (ρc): wani emitter mai juriya mai girma yawanci yana haifar da juriyar tuntuɓar ta tashi. Amma a hoto h, high-Rsheet double poly-Si (digogi ja) har yanzu yana riƙe ρc a matakin ƙasa, kusan 2-3 mΩ·cm². Ta hanyar ingantaccen metallization (LECO ko nano-second Joule heating, misali), emitter mai juriya mai girma na iya samar da kyakkyawar tuntuɓar ohmic, kuma babu wani bala'i na "high resistance meets high resistance" FF.
Aikace-aikacen Samfur
Lambobi uku masu wuya don layin samarwa
Haɗa bayanan simulation da aunawa a hotuna j zuwa l, ga wasu wuraren saukowa ga PE (injiniyoyin tsari) da PD (masu haɓaka samfur).
Sabon maƙalar juriyar takardar: 100-200 Ω/□ na gargajiya bazai zama mafi kyau ba. Bayanan suna nuna cewa matsawa zuwa kusan 430 Ω/□ (lanƙwasa ja a hoto e) yana ba da mafi kyawun rayuwa da sakamakon Voc. Amma yana buƙatar ingantaccen daidaiton tanderun bututu, in ba haka ba tasirin gefen yana ƙaruwa.
Cinikin ƙirar grid: rage faɗin layi daga 20 μm zuwa 10 μm yana sanya babban buƙatu akan daidaiton bugu na allo da rheology na azurfa. Filin simulation a hoto k yana nuna yanki mafi kyau na daidaitawa tsakanin grid pitch da juriyar takardar emitter, kuma rage faɗin yatsun ba tare da tunani ba yana sa juriyar jerin ta tashi sosai.
Makamin da ba a iya gani na poly biyu: madaidaicin halin yanzu-voltage (JV) a cikin hoto l yana nuna madaidaicin high-Rsheet double poly-Si shine mafi cikawa, ba tare da kink bayyananne ba. Wannan yana tabbatar da cewa tsarin Layer biyu yana aiki wajen danne zubar da jini, don haka high Voc a zahiri yana canzawa zuwa high PCE.
Tuntuɓi da Tattaunawa
Tubali da aka jefa ga takwarorinsu
Muna bin babban juriya na takarda a saman gaba (don Voc) da kuma grid masu kyau (don riƙe FF), da poly biyu a saman baya (don danne shigar Ag da ɗaga bifaciality). Da zarar kun tara wannan haɗin "gefe biyu-zuwa-matsananci", taga tsari yana matsewa sosai.
Babban juriya na boron diffusion a gaba yana sanya buƙatu masu tsanani akan tsaftace PSG da daidaiton ajiyar tushen boron. Poly biyu na baya yana buƙatar daidaiton girma a cikin ajiyar CVD da tsagewar laser.
Ga ainihin tambaya. Yayin da ingancin tantanin halitta ke tafiya zuwa iyakar ka'idar 26.7%, shin ya kamata mu ƙara ƙarin makamashi kan sarrafa daidaiton micro na kayan aiki (filin zafin bututun don yaduwar boron, daidaiton matakin ɗaukar CVD) maimakon ci gaba da tara sabbin matakai? Ga waɗanda ke aiki a kan layi, menene kuke ganin shine babban cikas da ke hana yawan samar da emitters masu juriya da poly biyu, iyawar kayan aiki ko tunanin haɗin tsari?
Ra'ayin Ooitech
A gaskiya, labarin nan ba game da sabon mataki ba ne, amma game da yadda taga ke ƙara ƙunci lokacin da kuka tura dukkan saman biyu lokaci guda. Yatsa mai 10 μm akan emitter 430 Ω/□ yana rayuwa ko mutuwa akan daidaiton bugu da daidaiton tanderu, don haka yaƙin yana motsawa daga "wane girke-girke" zuwa "yaya kayan aikina ke maimaitawa." A kan layin module, wannan tunani yana shafar haɗawa da haɗin kai, inda yatsu masu laushi da rauni ke azabtar da rashin kulawa. Ya cancanci biyan kuɗi zuwa tashar YouTube ta Ooitech (www.youtube.com/ooitech) idan kuna son ganin yadda wannan sha'awar daidaito ke aiki a filin.
