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20.1%‐efficient crystalline silicon solar cell with amorphous silicon rear‐surface passivation
Author(s) -
Schaper Martin,
Schmidt Jan,
Plagwitz Heiko,
Brendel Rolf
Publication year - 2005
Publication title -
progress in photovoltaics: research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.286
H-Index - 131
eISSN - 1099-159X
pISSN - 1062-7995
DOI - 10.1002/pip.641
Subject(s) - passivation , materials science , silicon , crystalline silicon , silicon nitride , ohmic contact , wafer , amorphous silicon , solar cell , nanocrystalline silicon , annealing (glass) , optoelectronics , amorphous solid , plasma enhanced chemical vapor deposition , aluminium , chemical vapor deposition , layer (electronics) , nanotechnology , metallurgy , chemistry , crystallography
We have developed a crystalline silicon solar cell with amorphous silicon (a‐Si:H) rear‐surface passivation based on a simple process. The a‐Si:H layer is deposited at 225°C by plasma‐enhanced chemical vapor deposition. An aluminum grid is evaporated onto the a‐Si:H‐passivated rear. The base contacts are formed by COSIMA (contact formation to a‐Si:H passivated wafers by means of annealing) when subsequently depositing the front silicon nitride layer at 325°C. The a‐Si:H underneath the aluminum fingers dissolves completely within the aluminum and an ohmic contact to the base is formed. This contacting scheme results in a very low contact resistance of 3.5 ±0.2 mΩ cm 2 on low‐resistivity (0.5 Ω cm) p ‐type silicon, which is below that obtained for conventional Al/Si contacts. We achieve an independently confirmed energy conversion efficiency of 20.1% under one‐sun standard testing conditions for a 4 cm 2 large cell. Measurements of the internal quantum efficiency show an improved rear surface passivation compared with reference cells with a silicon nitride rear passivation. Copyright © 2005 John Wiley & Sons, Ltd.