An isothermal etchback-regrowth method for high-efficiency Ga _1-xAl_xAs-GaAs solar cells

High-efficiency p-Ga1-xAlxAs, p-GaAs, n-GaAs solar cells are made by isothermally soaking n-GaAs substrates in an undersaturated Zn-doped Ga-Al-As melt. This one-step growth procedure produces a graded band gap p-Ga1-xAlxAs layer 0.2-0.4 μm thick. Efficiencies of 18.5% AM0 and 21.9% AM1 have been measured.