InP Solar Cell Development on Inexpensive Si Substrates.
Abstract
Optimized emitter/base dopants-At this point in the program, emitter designs have been roughly optimized for both P/N and N/P cells. For P/N cells, the emitter formation and cell junction depth are determined by zinc diffusion from the InGaAs contact cap. Zinc is a P-type dopant in InP. When we attempted to define epitaxially grown emitters, these emitters, which had thickness on the order of 1000A, were dominated by zinc diffusing out of the InGaAs contact cap, which effectively set the emitter depth at about 3000A. It therefore made little difference whether the epitaxially grown emitter layer was 100 or 1000A, since the junction depth was fixed by the zinc diffusing out of the InGaAs to 3000A. Spire was able to improve the P/N cell performance by controlling the thickness of the InGaAs cap layer, the solid state diffusion source for the zinc, as well as the growth temperature. Best cell performance was with a 1000A InGaAs cap thickness with the entire cell grown at 650 deg C. jg p.1
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 22, 1995
- Accession Number
- ADA293255