GaAs1-y-zPyBiz an alternative reduced bandgap alloy system lattice-matched to GaAs

The growth and properties of alloys in the alternative quaternary alloy system GaAs1yzPyBiz were explored. This materials system allows simultaneous and independent tuning of lattice constant and band gap energy, Eg, over a wide range for potential near- and mid-infrared optoelectronic applications by adjusting y and z in GaAs1yzPyBiz. Highly tensile-strained, pseudomorphic films of GaAs1yPy with a lattice mismatch strain of 1.2% served as the host for the subsequent addition of Bi. Lattice-matched alloy materials to GaAs were generated by holding y3.3z in GaAs1yzPyBiz. Epitaxial films with both high Bi content, z0.0854, and a smooth morphology were realized with measured band gap energies as low as 1.11-1.01 eV, lattice-matched to GaAs substrates. Density functional theory calculations are used to provide a predictive model for the band gap of GaAs1yzPyBiz lattice-matched to GaAs.