Band gap reduction and dielectric function of Ga_1−xZn_xN_1−xO_x and In_1−xZn_xN_1−xO_x alloys

Abstract

Abstract The band gap reductions, dielectric functions and absorption coefficients of the Ga 1− x Zn x N 1− x O x and In 1− x Zn x N 1− x O x ( x = 0.00, 0.25, 0.50, 0.75, and 1.00) alloys were calculated, employing the partial self‐consistent GW approximation. As a comparison, the local density approximation (LDA) and the Heyd–Scueria–Ernzerhof (HSE) hybrid functional were also used to calculate the gap reduction. Both Ga 1− x Zn x N 1− x O x and In 1− x Zn x N 1− x O x alloys show strong band gap bowing. As a result, the band gap energy in Ga 1− x Zn x N 1− x O x is reduced by E g (GaN) − E g (Ga 1− x Zn x N 1− x O x ) = 1.61, 2.01 and 1.91 eV for x = 0.25, 0.50, and 0.75, respectively. This allows optoelectronic devices based on GaN and ZnO with more efficient absorption or emission of light in the visible light range. The calculated dielectric functions and absorption spectra demonstrate that the band gap reduction enhances the optical absorption around the 2.5 eV region. Interestingly, the In 1− x Zn x N 1− x O x alloy with x = 0.25 has the large optical absorption coefficient in the energy region 0.69–6.0 eV, and the alloy has very good absorption at 2–3 eV.