Room temperature photoluminescence intensity enhancement in GaAs1-xBix alloys

The optical properties of GaAs1-xBix alloys with Bi compositions between 0.022 and 0.06 have been studied by photoluminescence (PL). The samples were grown at 400 degrees C using molecular beam epitaxy. At room temperature, the incorporation of Bi in GaAs reduces the band gap by 64 meV/% Bi with peak wavelength of 1.2 mu m for x = 0.06. It was found that room temperature PL intensity increased with Bi composition, but decreases with composition at 10 K. The results at 10 K suggest that the incorporation of Bi degrades the crystal quality. However, the effect is negated by more efficient carrier confinement as a result of larger band gap offset between GaAs1-xBix and GaAs at room temperature. Hence, the room temperature PL intensity continues to increase monotonically for x up to 0.06. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim