GaAs1−y−zPyBiz, an alternative reduced band gap alloy system lattice-matched to GaAs

Abstract

The growth and properties of alloys in the alternative quaternary alloy system GaAs1−y−zPyBiz 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 GaAs1−y−zPyBiz. Highly tensile-strained, pseudomorphic films of GaAs1−yPy 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 y ∼ 3.3z in GaAs1−y−zPyBiz. Epitaxial films with both high Bi content, z ∼ 0.0854, 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 GaAs1−y−zPyBiz lattice-matched to GaAs.

Enhanced Incorporation of P into Tensile-Strained GaAs1-yPyLayers Grown by Metal-Organic Vapor Phase Epitaxy at Very Low Temperatures

“…This enhanced incorporation of P at low temperatures suggests the feasibility of applying PH 3 for the low temperature growth of GaAs 1-y P y as well as other P-containing quaternary alloy systems, such as GaAs 1-x-y P x Bi y . 22 …”

“…High temperature growth of these alloys often leads to phase separation as predicted by the equilibrium phase diagrams. The recent investigation of phosphorous containing metastable quaternary alloys, such as GaAs 1-x-y P x Bi y , 22 also requires low growth temperatures. Low growth temperatures are also known to extend the pseudomorphic limit by suppressing thermally-activated dislocation nucleation and glide.…”

Theory of the Electronic and Optical Properties of Dilute Bismide Quantum Well Lasers

“…However, while no GaBi x As 1−x QW lasers have yet been developed with sufficiently high Bi compositions to suppress the dominant CHSH Auger recombination mechanism, progress in developing dilute bismide QW lasers has been rapid and efforts to reach this important milestone are ongoing. For example, recent investigations of GaBi x P y As 1−x−y alloys have shown that incorporation of a small amount of phosphorus (P) enhances Bi incorporation during MOVPE growth [30], while also providing the possibility to grow dilute bismide laser structures which are lattice-matched to GaAs. Although it is likely to be related to the P-induced reduction of compressive strain in the quaternary alloy, the precise mechanism by which co-alloying P and Bi enhances Bi incorporation has yet to be determined.…”

Surface effects of vapour-liquid-solid driven Bi surface droplets formed during molecular-beam-epitaxy of GaAsBi

“…In most cases, experimental probes are far larger than the dimensions of the droplets/tracks on the surface (order of nm to μ m7891011171934), with measurements unavoidably recording an unresolved average of the entire probed area. While the removal of Bi surface droplets post growth (through selective wet chemical etching), and prior to characterisation, appears to rid the Bi metal, a number of experimental studies383940 have neglected to consider their lasting impact on the structural and optical properties of the epitaxial surface. This issue we investigate in the present study using electron microscopy techniques and micro-optical probes (lateral resolution ~1 μ m).…”