Effects of molecular beam epitaxy growth conditions on composition and optical properties of InxGa1-xBiyAs1-y

We describe the growth conditions of InxGa1-xBiyAs1-y (lattice-mismatched and matched) on InP substrates by molecular beam epitaxy and the resulting properties. Due to their anomalously narrow bandgaps and the presence of bismuth, these materials are promising for optoelectronics and thermoelectrics. Low growth temperature and moderate As/Bi beam equivalent pressure ratios are beneficial for Bi incorporation, in good qualitative agreement with GaBiyAs1-y on GaAs. Up to 6.75% bismuth is incorporated. High resolution x-ray diffraction and reciprocal space mapping show that InxGa1-xBiyAs1-y samples exhibit good crystalline quality and zero relaxation. The band gap is reduced in agreement with theoretical predictions. Lattice-matched samples have been produced with lattice mismatch <= 0.21%. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3695066]