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Control of preferential orientation of microcrystalline silicon and its impact on solar cell performance
Author(s) -
Saito Kimihiko,
Kondo Michio
Publication year - 2011
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.1053
Subject(s) - volume fraction , silane , microcrystalline , solar cell , materials science , hydrogen , silicon , analytical chemistry (journal) , volume (thermodynamics) , passivation , amorphous solid , chemistry , crystallography , nanotechnology , optoelectronics , composite material , organic chemistry , physics , quantum mechanics , layer (electronics)
The significance of preferential orientation in microcrystalline silicon for its post‐oxidation properties and solar cell performance has been investigated in the high crystalline volume fraction range. The degree of <110> preferential orientation can be varied by changing hydrogen/silane ratio in plasma enhanced chemical vapor deposition, and the crystalline volume fraction is lowered for a <110> oriented sample at the low hydrogen dilution ratio. In this study, we have improved the volume fraction by a seeding method, and, even under low hydrogen dilution, we have successfully controlled the preferential orientation of the samples with equivalently high crystalline‐volume‐fraction. Films in strong <110>‐preferential‐orientation show little amount of post‐oxidation, and the sharp signal at around 2100 cm −1 in the infrared (IR) absorption spectrum appears as the preferential orientation turns from the <110> to the <111> direction. The solar cell performance well agrees with the post‐oxidation properties. The origin of these preferential orientation impacts on post‐oxidation and on solar cell performance is discussed in terms of amorphous silicon passivation on the grain boundaries (GBs) presumably influenced by hydrogen/silane ratio. Copyright © 2010 John Wiley & Sons, Ltd.