Band-gap narrowing in ordered Ga0.47In0.53As

Abstract

We report the first observation of band-gap energy reduction in Ga0.47In0.53As deposited on (100) InP by atmospheric pressure organometallic vapor phase epitaxy due to CuPt-type ordering. A reduction of more than 65 meV in the band-gap energy is observed for lattice-matched samples that show strong CuPt-like ordering by transmission electron microscopy. By comparison samples that show no CuPt-like ordering diffraction signatures, do not have reduced band-gap energies. Studies of the influence of growth parameters on the band-gap energy indicate a U-shaped dependence on the growth temperature with a minimum around 550 °C and decreasing band-gap energies with increasing growth rate (at a constant V/III ratio) over the range 0.5–4 μm/h.