Title :
Modification of textured silicon wafer surface morphology for fabrication of heterojunction solar cell with open circuit voltage over 700 mV
Author :
Fesquet, L. ; Olibet, S. ; Damon-Lacoste, J. ; De Wolf, S. ; Hessler-Wyser, A. ; Monachon, C. ; Ballif, C.
Author_Institution :
Thin Film Electron. Lab., Ecole Polytech. Fed. de Lausanne (EPFL), Neuchatel, Switzerland
Abstract :
Crystalline silicon wafer (c-Si) can be extremely well passivated by plasma enhanced chemical vapor deposited (PECVD) amorphous silicon (a-Si:H) films. As a result, on flat substrates, solar cells with very high open circuit voltage are readily obtained. On textured substrates however the passivation is more cumbersome, likely due to the presence of localized recombinative paths situated at the pyramid valleys. Here, we show that this issue may be resolved by selecting a silicon substrate morphology featuring large pyramids. Chemical post-texturization treatments can further reduce the surface recombination velocity. This sequence has allowed us to fabricate solar cells with open circuit voltage over 700 mV, demonstrating also on device level the effect of pyramid density and surface micro-roughness on the surface passivation quality.
Keywords :
amorphous semiconductors; elemental semiconductors; passivation; plasma CVD coatings; semiconductor heterojunctions; semiconductor thin films; silicon; solar cells; surface morphology; surface roughness; surface texture; PECVD; Si; amorphous silicon films; crystalline silicon wafer; heterojunction solar cell; open circuit voltage; passivation; plasma enhanced chemical vapor deposited; pyramid density effect; silicon substrate morphology; surface microroughness; textured silicon wafer surface morphology; Chemicals; Circuits; Fabrication; Heterojunctions; Photovoltaic cells; Silicon; Surface morphology; Surface texture; Surface treatment; Voltage;
Conference_Titel :
Photovoltaic Specialists Conference (PVSC), 2009 34th IEEE
Conference_Location :
Philadelphia, PA
Print_ISBN :
978-1-4244-2949-3
Electronic_ISBN :
0160-8371
DOI :
10.1109/PVSC.2009.5411173