Abstract
First-principles calculations based on density functional theory have been performed for the quaternary GaAs1-x-y N x Bi y alloy lattice-matched to GaAs. Using the state-of-the-art computational method with the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional, electronic, and optical properties were obtained, including band structures, density of states (DOSs), dielectric function, absorption coefficient, refractive index, energy loss function, and reflectivity. It is found that the lattice constant of GaAs1-x-y N x Bi y alloy with y/x =1.718 can match to GaAs. With the incorporation of N and Bi into GaAs, the band gap of GaAs1-x-y N x Bi y becomes small and remains direct. The calculated optical properties indicate that GaAs1-x-y N x Bi y has higher optical efficiency as it has less energy loss than GaAs. In addition, it is also found that the electronic and optical properties of GaAs1-x-y N x Bi y alloy can be further controlled by tuning the N and Bi compositions in this alloy. These results suggest promising applications of GaAs1-x-y N x Bi y quaternary alloys in optoelectronic devices.
Highlights
In recent years, the synthesis of semiconductor alloys with specific structures, electronic, and optical properties is widely demanded in the application of photoelectric devices, and a great deal of effort has been devoted to explore some nonconventional alloys, especially for III-V compound semiconductors
As can be seen from the projected density of states (DOSs) of GaAs1-x-yNxBiy in Figure 1e,f, N doping mainly contributes to the conduction band, leading to the conduction band minimum moves towards the Fermi energy, and Bi doping mainly contributes to the valence band, resulting in a reduced band gap due to the intraband level repulsions, consistent with the previous research [10]
(i) With the incorporation of N and Bi into GaAs, the band gap of GaAs1-x-yNxBiy lattice-matched to GaAs has a significant reduction
Summary
The synthesis of semiconductor alloys with specific structures, electronic, and optical properties is widely demanded in the application of photoelectric devices, and a great deal of effort has been devoted to explore some nonconventional alloys, especially for III-V compound semiconductors. InGaAsP, BInGaAs, and BGaAsSb have been investigated adequately from the aspects of structure, electronic, and optical properties for their potential applications in lasers, detectors, solar cells, etc. Due to the large atomic size mismatch between As and N, it is difficult to grow high-quality GaAs1-xNx alloy on GaAs substrates. By substituting large-atom X, the new alloy XGaAsN can be made lattice-matched to GaAs. Most of the previous research works put emphasis on InyGa1-yAs1-xNx grown on a
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