Title :
Microcrystalline-crystalline silicon heterojunction solar cells using highly conductive thin p-type microcrystalline silicon window layers
Author :
van Cleef, M.W.M. ; Rath, J.K. ; Rubinelli, F.A. ; van der Werf, C.H.M. ; Schropp, R.E.I.
Author_Institution :
Dept. of Atomic & Interface Phys., Utrecht Univ., Netherlands
Abstract :
Microcrystalline-crystalline silicon heterojunction solar cells were made using thin (20 nm) p+μc-Si:H window layers on top of 1 Ωcm n-type c-Si. Microcrystalline layers were obtained using moderate PECVD deposition conditions and showed appreciable crystalline volume fraction (~22%), and good window properties. Solar cells made with such window layers have the following structure: Ag/ITO/p+ μc-Si:H/buffer/n-c-Si/Al. The presence of a thin (~2 nm) intrinsic a-Si buffer layer deposited at low temperature was found to be essential to achieve high Voc and efficiencies. From simulation studies, the authors found that the wide band gap buffer layer reduces the recombination losses occurring in the low mobility gap p+ μc-Si:H layer which explains the higher Voc values. The highest efficiency (12.2%) was obtained on cells with a 2.5 nm buffer layer deposited after an extra atomic hydrogen pretreatment of the n-type c-Si
Keywords :
amorphous semiconductors; electron-hole recombination; elemental semiconductors; energy gap; hydrogen; p-n heterojunctions; plasma CVD; plasma CVD coatings; semiconductor device models; semiconductor doping; semiconductor thin films; silicon; solar cells; 12.2 percent; 2 nm; 2.5 nm; 20 nm; PECVD deposition; Si:H-Si-Si; Si:H/a-Si/Si heterojunction solar cells; atomic hydrogen pretreatment; crystalline volume fraction; intrinsic a-Si buffer layer deposition; low mobility gap; microcrystalline Si window layers; open-circuit voltage; recombination losses; simulation; window properties; Atomic layer deposition; Buffer layers; Crystallization; Heterojunctions; Hydrogen; Indium tin oxide; Photovoltaic cells; Silicon; Temperature; Wideband;
Conference_Titel :
Photovoltaic Specialists Conference, 1996., Conference Record of the Twenty Fifth IEEE
Conference_Location :
Washington, DC
Print_ISBN :
0-7803-3166-4
DOI :
10.1109/PVSC.1996.564035