High Quality GaAs on Si and its Application to a Solar Cell

Abstract

ABSTRACTEpitaxial growth using thermal annealing and a strained layer superlattice is studied to obtain high-quality GaAs device layers on Si substrates. Crystalline quality of GaAs-on-Si is found to improve with thermal cyclic annealing at temperatures higher than the growth temperature and cooling down to 300°C. It is also found that the optimum InGaAs/GaAs strained layer superlattice buffer structure is one whose total thickness is several times the calculated critical thickness for the average In-mole fraction of the SLS buffer. Configurations and structures of dislocation reductions are ex-amined by TEM observations. A GaAs solar cell is successfully constructed and is found to show total area efficiencies of 18.3% under AM 0 and 20.0% under AM 1.5 conditions.