Photovoltaic Effect and Luminescences of AlxGa1-xSb Ternary Alloy Semiconductors

Single crystals of Al x Ga1-x Sb were prepared by the solution growth method, and the band gaps of the alloys were derived from the photovoltaic responses obtained at room temperature. The polarity of the photovoltage shows intentionally undoped alloys to be n-type, in contrast to the usual results. This is due to the large amount of Si impurities introduced from the quartz container by reaction with Al during the high-temperature growth. The photo- and electroluminescent spectra were measured at 80 K, and three series of peaks were observed in both luminescences. These are interpreted in terms of recombinations of interband transitions, via Si impurities and residual impurities, perhaps Sb vacancies, which always exist in undoped GaSb.