Indium Gallium Arsenide Electron and Phonon Properties Study by Density Functional Theory

Abstract

Indium gallium arsenide(InGaAs) is a promising channel material for high-frequency applications due to its superior electron mobility property[1]. However, there is a lack of research about the electronic transport property of InGaAs. The property is calculated by Monte Carlo simulation that solves the Boltzmann transport equation[2]. And, electron and phonon properties are used to run Monte Carlo simulation. So, we report electron and phonon properties by density functional theory using quantum espresso. We made InxGa1-x pseudopotential, covering a composition range from x=0.05 to x=0.95, by combining Indium and Gallium Local-density approximation(LDA) pseudopotential. Subsequently, we calculated optimized lattice structures of InxGa1-xAs, InAs and GaAs. Afterwards, we calculated electronic band gaps, phonons, and electron-phonon(e-ph) coupling by using optimized lattice structures. Fig. 1 shows the calculated and experimental value of band gaps. Fig. 2 shows the In0.5Ga0.5As phonon dipsersion. We compared calculated and experimental wave number of InAs and GaAs at Γ(TO), Γ(LO), X(TA), X(LA), X(TO), X(LO), L(TA), L(LA), L(TO), L(LO). Average error rate of InAs is 5.76% and of GaAs is 1.77%. we could check that phonon dispersion of In0.5Ga0.5As represents the medium value of InAs and GaAs. And, e-ph matrix element was calculated in first Brillouin. And, Fig. 3 shows e-ph matrix element of In0.5Ga0.5As when electron state was at Γ, phonon state was from (-0.5, -0.5, 0) to (0.5, 0.5, 0) and phonon mode was LO. To conclude, band gaps and phonons have good agreement with experimental value when we consider LDA pseudopotential underates band gap. And, e-ph matrix elements are calculated reasonably because they show reflection symmetry about the qx=qy axis and high value at LO. our results can pave way to develop InGaAs high-frequuency devices.