OMVPE growth and characterization of Bi-containing III–V alloys

Abstract

For potential infrared detector applications, single crystalline InAsBi and InAsSbBi have been grown by atmospheric pressure OMVPE. Good quality epilayers with smooth surface morphologies were obtained by properly controlling the key growth parameter, the V/III ratio. The variation of lattice constant with solid composition for the InAs 1− x Bi x system, a = 6.058 + 0.966ß, provides evidence that Bi atoms incorporate substitutionally into the group V sublattice in the InAs zincblende structure. An extrapolated lattice parameter for the hypothetical zincblende InBi is 7.024Å. Thermodynamic calculations using the delta-lattice-parameter model predict that tremendously large miscibility gaps exist in the alloy system. Nevertheless, metastable InAsBi and InAsSbBi alloys were grown with concentrations far exceeding the solubility limit. For example 4.0 at% Bi was incorporated into InAs. Infrared photoluminescence measurements show a decrease of peak energy with increasing Bi concentration in the alloys, with d E g/d x=-55 meV/at% Bi. A study of the transmission spectra of these Bi-containing alloys confirms the above result.