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Title: Indium phosphide/cadmium sulfide thin-film solar cells

Technical Report ·
DOI:https://doi.org/10.2172/5439726· OSTI ID:5439726

Thin-film InP/CdS structures were prepared by depositing, in sequence, ITO on a low-cost glass substrate, CdS on the ITO by thermal evaporation, and InP on the CdS by planar reactive deposition (PRD). Films of CdS, 15 ..mu..m thick, were recrystallized in flowing H/sub 2//H/sub 2/S at 500/sup 0/C. Lateral dimensions of typical grains were 50..mu..m with values up to 200 ..mu..m. The sheet resistance of the recrystallized CdS (RXCdS) was lowered from greater than 10/sup 5/ ..cap omega../O = cm/sup 2/ to values as low as 16 ..cap omega../O = cm/sup 2/ by annealing in either H/sub 2/ Cd atmospheres. Epitaxy of InP was undertaken on (100) InP at a substrate temperature of 320/sup 0/C. Room-temperature electron mobilities of about 2000 cm/sup 2//V-sec were found. Mobilities and hole concentrations of 60 cm/sup 2//V-sec and 10/sup 17/ cm-/sup 3/, respectively, were achieved with Be-doped films. P-type films with hole concentrations as high as a few times 10/sup 18/cm-/sup 3/ were achieved with increased doping. Be-doped InP was deposited onto the RXCdS/ITO/GLASS substrate to form a thin-film cell. However, p-type InP could not be prepared with CdS as a substrat4e, presumably due to interdiffusion or vapor transport of sulfur. Consequently, blocking action and a photovoltage could only be achieved using a gold Schottky barrier on the InP/RXCdS/ITO/GLASS structure. Plans for the next quarter include determining whether n-type doping from the CdS occurs by either interdiffusion or vapor transport, characterizing InP epitaxy on the RXCdS, and preparing additional thin-film structures.

Research Organization:
Hughes Research Labs., Malibu, CA (USA)
DOE Contract Number:
EG-77-C-01-4042
OSTI ID:
5439726
Report Number(s):
DSE-4042-T25
Country of Publication:
United States
Language:
English