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Title: Distribution of Local Open-Circuit Voltage on Amorphous and Nanocrystalline Mixed-Phase Si:H and SiGe:H Solar Cells: Preprint

Abstract

Local open-circuit voltage (Voc) distributions on amorphous and nanocrystalline mixed-phase silicon solar cells were measured using a scanning Kelvin probe microscope (SKPM) on the p layer of an n-i-p structure without the top ITO contact. During the measurement, the sample was illuminated with a laser beam that was used for the atomic force microscopy (AFM). Therefore, the surface potential measured by SKPM is the sum of the local Voc and the difference in workfunction between the p layer and the AFM tip. Comparing the SKPM and AFM images, we find that nanocrystallites aggregate in the amorphous matrix with an aggregation size of {approx}0.5 ..mu..m in diameter, where many nanometer-size grains are clustered. The Voc distribution shows valleys in the nanocrystalline aggregation area. The transition from low to high Voc regions is a gradual change within a distance of about 1 ..mu..m. The minimum Voc value in the nanocrystalline clusters in the mixed-phase region is larger than the Voc of a nc-Si:H single-phase solar cell. These results could be due to lateral photo-charge redistribution between the two phases. We have also carried out local Voc measurements on mixed-phase SiGe:H alloy solar cells. The magnitudes of Voc in the amorphous and nanocrystallinemore » regions are consistent with the J-V measurements.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
891538
Report Number(s):
NREL/CP-520-39882
TRN: US200622%%80
DOE Contract Number:
AC36-99-GO10337
Resource Type:
Conference
Resource Relation:
Conference: Presented at the 2006 IEEE 4th World Conference on Photovoltaic Energy Conversion (WCPEC-4), 7-12 May 2006, Waikoloa, Hawaii
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; ALLOYS; ATOMIC FORCE MICROSCOPY; DISTRIBUTION; ENERGY CONVERSION; LASERS; MICROSCOPES; ORGANIC COMPOUNDS; PROBES; SILICON SOLAR CELLS; SOLAR CELLS; SURFACE POTENTIAL; VOLATILE MATTER; PV; OPEN-CIRCUIT VOLTAGE; AMORPHOUS; NANOCRYSTALINE; SCANNING KELVIN PROBE MICROSCOPE (SKPM); ATOMIC FORCE MICROSCOPY (AFM); Solar Energy - Photovoltaics

Citation Formats

Jiang, C.-S., Moutinho, H. R., Al-Jassim, M. M., Kazmerski, L. L., Yan, B., Owens, J. M., Yang, J., and Guha, S. Distribution of Local Open-Circuit Voltage on Amorphous and Nanocrystalline Mixed-Phase Si:H and SiGe:H Solar Cells: Preprint. United States: N. p., 2006. Web. doi:10.1109/WCPEC.2006.279780.
Jiang, C.-S., Moutinho, H. R., Al-Jassim, M. M., Kazmerski, L. L., Yan, B., Owens, J. M., Yang, J., & Guha, S. Distribution of Local Open-Circuit Voltage on Amorphous and Nanocrystalline Mixed-Phase Si:H and SiGe:H Solar Cells: Preprint. United States. doi:10.1109/WCPEC.2006.279780.
Jiang, C.-S., Moutinho, H. R., Al-Jassim, M. M., Kazmerski, L. L., Yan, B., Owens, J. M., Yang, J., and Guha, S. Mon . "Distribution of Local Open-Circuit Voltage on Amorphous and Nanocrystalline Mixed-Phase Si:H and SiGe:H Solar Cells: Preprint". United States. doi:10.1109/WCPEC.2006.279780. https://www.osti.gov/servlets/purl/891538.
@article{osti_891538,
title = {Distribution of Local Open-Circuit Voltage on Amorphous and Nanocrystalline Mixed-Phase Si:H and SiGe:H Solar Cells: Preprint},
author = {Jiang, C.-S. and Moutinho, H. R. and Al-Jassim, M. M. and Kazmerski, L. L. and Yan, B. and Owens, J. M. and Yang, J. and Guha, S.},
abstractNote = {Local open-circuit voltage (Voc) distributions on amorphous and nanocrystalline mixed-phase silicon solar cells were measured using a scanning Kelvin probe microscope (SKPM) on the p layer of an n-i-p structure without the top ITO contact. During the measurement, the sample was illuminated with a laser beam that was used for the atomic force microscopy (AFM). Therefore, the surface potential measured by SKPM is the sum of the local Voc and the difference in workfunction between the p layer and the AFM tip. Comparing the SKPM and AFM images, we find that nanocrystallites aggregate in the amorphous matrix with an aggregation size of {approx}0.5 ..mu..m in diameter, where many nanometer-size grains are clustered. The Voc distribution shows valleys in the nanocrystalline aggregation area. The transition from low to high Voc regions is a gradual change within a distance of about 1 ..mu..m. The minimum Voc value in the nanocrystalline clusters in the mixed-phase region is larger than the Voc of a nc-Si:H single-phase solar cell. These results could be due to lateral photo-charge redistribution between the two phases. We have also carried out local Voc measurements on mixed-phase SiGe:H alloy solar cells. The magnitudes of Voc in the amorphous and nanocrystalline regions are consistent with the J-V measurements.},
doi = {10.1109/WCPEC.2006.279780},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2006},
month = {Mon May 01 00:00:00 EDT 2006}
}

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