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Title: Investigation of Cd1-xMgxTe Alloys for Tandem Solar Cell Applications

Abstract

Theoretical modeling of two-junction tandem solar cells shows that for optimal device performance, the bandgap of the top cell should be in the range of 1.6 to 1.8 eV. Cd{sub 1-x}Mg{sub x}Te (CMT) alloys have a lattice constant close to that of CdTe, and the addition of a small amount of Mg changes the bandgap considerably. In this paper, we present our work on developing CMT for solar cell applications. CMT films were prepared by vacuum deposition with co-evaporation of CdTe and Mg on substrates heated to 300-400 C. Films with a composition in the range of x=0 to 0.66 were fabricated, and optical analysis of the films showed that the bandgap of the samples ranged from 1.5 to 2.3 eV and varied linearly with composition. For the fabrication of devices using these alloy films, we also investigated the effect of post-deposition CdCI2 heat treatment. We have investigated junctions between CdS and CMT alloys in the bandgap range of 1.5 to 1.8 eV for tandem cell applications. We have also worked on the ohmic contacts to the CMT alloy films using Cu/Au bilayers, and the preliminary data shows a significant effect of the contact processing on the device performance. Wemore » present the results on the materials properties of these alloys and the effect of post deposition treatments on the film properties and device performance for different alloy compositions and compare them to similar CdTe devices to determine their applicability in tandem solar cell applications.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
943997
DOE Contract Number:
AC36-99-GO10337
Resource Type:
Conference
Resource Relation:
Conference: [Proceedings] 2006 IEEE 4th World Conference on Photovoltaic Energy Conversion (WCPEC-4), 7-12 May 2006, Waikoloa, Hawaii; Related Information: For preprint version see NREL/CP-520-39899
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; ALLOYS; DEPOSITION; ENERGY CONVERSION; FABRICATION; HEAT TREATMENTS; PERFORMANCE; PROCESSING; SIMULATION; SOLAR CELLS; SUBSTRATES; Solar Energy - Photovoltaics; Silicon Materials and Devices

Citation Formats

Dhere, R., Ramanathan, K., Scharf, J., Moutinho, H., To, B., Duda, A., and Noufi, R. Investigation of Cd1-xMgxTe Alloys for Tandem Solar Cell Applications. United States: N. p., 2006. Web. doi:10.1109/WCPEC.2006.279513.
Dhere, R., Ramanathan, K., Scharf, J., Moutinho, H., To, B., Duda, A., & Noufi, R. Investigation of Cd1-xMgxTe Alloys for Tandem Solar Cell Applications. United States. doi:10.1109/WCPEC.2006.279513.
Dhere, R., Ramanathan, K., Scharf, J., Moutinho, H., To, B., Duda, A., and Noufi, R. Sun . "Investigation of Cd1-xMgxTe Alloys for Tandem Solar Cell Applications". United States. doi:10.1109/WCPEC.2006.279513.
@article{osti_943997,
title = {Investigation of Cd1-xMgxTe Alloys for Tandem Solar Cell Applications},
author = {Dhere, R. and Ramanathan, K. and Scharf, J. and Moutinho, H. and To, B. and Duda, A. and Noufi, R.},
abstractNote = {Theoretical modeling of two-junction tandem solar cells shows that for optimal device performance, the bandgap of the top cell should be in the range of 1.6 to 1.8 eV. Cd{sub 1-x}Mg{sub x}Te (CMT) alloys have a lattice constant close to that of CdTe, and the addition of a small amount of Mg changes the bandgap considerably. In this paper, we present our work on developing CMT for solar cell applications. CMT films were prepared by vacuum deposition with co-evaporation of CdTe and Mg on substrates heated to 300-400 C. Films with a composition in the range of x=0 to 0.66 were fabricated, and optical analysis of the films showed that the bandgap of the samples ranged from 1.5 to 2.3 eV and varied linearly with composition. For the fabrication of devices using these alloy films, we also investigated the effect of post-deposition CdCI2 heat treatment. We have investigated junctions between CdS and CMT alloys in the bandgap range of 1.5 to 1.8 eV for tandem cell applications. We have also worked on the ohmic contacts to the CMT alloy films using Cu/Au bilayers, and the preliminary data shows a significant effect of the contact processing on the device performance. We present the results on the materials properties of these alloys and the effect of post deposition treatments on the film properties and device performance for different alloy compositions and compare them to similar CdTe devices to determine their applicability in tandem solar cell applications.},
doi = {10.1109/WCPEC.2006.279513},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}

Conference:
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