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Title: Cadmium telluride films and solar cells

Journal Article · · IEEE Trans. Electron Devices; (United States)

CdTe thin films for solar cell applications have been deposited by close-spaced vapor transport and by hot-wall vacuum evaporation. As-deposited films are p-type with hole densities that increase to values of 1 X 10/sup 16/ cm/sup -3/ with increasing substrate temperature. A variety of experimental results can be interpreted either in terms of doping by native defects such as cadmium vacancies or doping by diffusion from the graphite substrate, with evidence for self-compensation. Many CdS/CdTe/graphite solar cells have been prepared by vacuum evaporation of CdS onto thin-film CdTe, which have low values of J /SUB o/ about 10/sup -9/ A/cm/sup 2/ and high values of J /SUB sc/ about 17 mA/cm/sup 2/. The open-circuit voltage is low at 0.48 V for CdS deposition at 300/sup 0/C, but increases with decreasing CdS deposition temperature. The highest efficiency prepared to date is 6.4 percent. The efficiency is limited at present by the fill factor, associated with a total series resistivity in the light of the order of 10 ..cap omega..-cm/sup 2/. Supporting research on low-resistance contacts to p-type CdTe, grain boundary properties and passivation in p-type CdTe bicrystals and thin films, and high-resolution transmission electron microscopy of junction interfaces is briefly described.

Research Organization:
Department of Materials Science and Engineering, Stanford Univ., Stanford, CA
OSTI ID:
6155689
Journal Information:
IEEE Trans. Electron Devices; (United States), Vol. ED-31:5
Country of Publication:
United States
Language:
English