Bismide-nitride alloys: Promising for efficient light emitting devices in the near- and mid-infrared

Abstract

GaAsBiN is a potentially interesting alloy which may be exploited in near- and mid-infrared photonic devices. Here we present the predicted band parameters such as band gap (Eg), the spin-orbit splitting energy (ΔSO), band offsets and strain of GaAsBiN on GaAs versus N and Bi compositions based on recent experimental data. We also show how bismuth may be used to form alloys whereby ΔSO > Eg thereby providing a means of suppressing non-radiative CHSH (hot-hole producing) Auger recombination and inter-valence band absorption. We determine the optimum conditions where ΔSO > Eg, which is expected to improve the high-temperature performance and thermal stability of light emitting devices. It is also shown that preferential band offsets are achievable with GaAsBiN, which makes this material system promising for photonic devices operating in the near- and mid-infrared.

Novel Dilute Bismide, Epitaxy, Physical Properties and Device Application

“…Other beneficial properties when using Bi include large spin-orbit (SO) split band [46,47], less temperature sensitive bandgap [32,48,49], minor influence on both electron [50] and hole mobility [51] for small Bi concentrations, enhancement of PL intensity [44] and surfactant effect ensuring smooth surface [52], etc. Sweeney and Jin proposed theoretically that GaAsNBi is promising for efficient near IR light emitting devices [53]. When the SO split energy is larger than the bandgap, Auger recombination involving holes in the SO and the heavy-hole band and inter-valence band absorption (IVBA) will be suppressed, which is expected to improve high-temperature performance and thermal stability of light emitting devices.…”

“…Such a reduction results from interaction between extended states of the host alloy and the localized states of the Bi impurities [59]. The dilute bismide alloys can present ∆ SO > E g condition, which is an optimal condition to suppress non-radiative CHSH (Conduction-Heavy hole Spin-orbit-Heavy hole) Auger recombination and IVBA, and to improve the performance in high temperature and thermal stability of light emitting devices [53,59,61,62]. Carrier mobility and concentrations for the In y Ga 1−y Bi x As 1−x system have also been computed with this model [62].…”

“…This model always combines with experimental data to give the interaction strength. For example, the experimental data of GaAsBiN alloys on GaAs [53,59] and that of InGaAsBi alloys on InP [61,62] were used in the model to account for the reduction of bandgap as well as an increase in the SO split energy with increasing Bi concentration. Such a reduction results from interaction between extended states of the host alloy and the localized states of the Bi impurities [59].…”

Impact of alloy disorder on the band structure of compressively strained GaBixAs1−x

“…[5][6][7][8] When a small fraction of As is replaced by Bi in GaAs, the energy gap E g decreases rapidly, by ≈90 meV when 1% of As is replaced by Bi. In addition, photoreflectance measurements show that the energy separation, SO , between the spin-split-off valence band and the valence band edge also increases rapidly with Bi composition.…”

GaAs-based dilute bismide semiconductor lasers: Theory vs. experiment

“…The growing interest in these "highlymismatched" materials is due to fundamental interest in the unusual properties of dilute bismide alloys, as well as their potential for specific device applications. Of particular interest is the exploitation of the effects of Bi incorporation to facilitate band structure engineering in semiconductor lasers [1]- [4].…”