Low-cost, high-efficiency solar cells utilizing GaAs-on-Si technology. Annual subcontract report, 1 August 1991--31 July 1992.

摘要

This report describes work to develop technology to deposit GaAs on Si using a nucleation layer of atomic-layer-epitaxy-grown GaAs or AlAs on Si. This ensures two-dimensional nucleation and should lead to fewer defects in the final GaAs layer. As an alternative, we also developed technology for depositing GaAs on sawtooth-patterned Si. Preliminary studies showed that this material can have a very low defect density, (approximately) 1 (times) 10(sup 5) cm(sup (minus)5), as opposed to our conventionally grown GaAs on SL which has a typical defect density of over 1 (times)10(sup 7) cm(sup (minus)2). Using these two new methods of GaAs-on-Si material growth, we made solar cells that are expected to show higher efficiencies than those of previous cells.