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Light-Induced Passivation of Si by Iodine Ethanol Solution

Published online by Cambridge University Press:  21 March 2011

Bhushan Sopori
Affiliation:
National Renewable Energy Laboratory, Golden, CO 80401
Przemyslaw Rupnowski
Affiliation:
National Renewable Energy Laboratory, Golden, CO 80401
Jesse Appel
Affiliation:
National Renewable Energy Laboratory, Golden, CO 80401
Debraj Guhabiswas
Affiliation:
National Renewable Energy Laboratory, Golden, CO 80401
LaTecia Anderson-Jackson
Affiliation:
North Carolina Agricultural and Technical State University, Greensboro, NC, 27411
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Abstract

We report on our observations of light-activated passivation (LIP) of Si surfaces by iodine-ethanol (I-E) solution. Based on our experimental results, the mechanism of passivation appears to be related to dissociation of iodine by the photo-carriers injected from the Si wafer into the I-E solution. The ionized iodine (I) then participates in the formation of a Si-ethoxylate bond that passivates the Si surface. Experiments with a large number of wafers of different material parameters indicate that under normal laboratory conditions, LIP can be observed only in some samples–samples that have moderate minority-carrier lifetime. We explain this observation and also show that wafer cleaning plays an extremely important role in passivation.

Type
Research Article
Copyright
Copyright © Materials Research Society 2009

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