Effect of pressure on the energy band gaps of wurtzite GaN and AlN and electronic properties of their ternary alloys AlxGa1−xN

Using the Empirical Pseudopotential Method (EPM) combined with an improved Virtual Crystal Approximation (VCA), where the effect of compositional disorder is included as an effective periodic potential, we have calculated the electronic band structure of GaN and AlN under hydrostatic pressure up to 200 kbar and 160 kbar, respectively. The behavior of electronic properties of their alloys AlxGa1−xN in the wurtzite structure have been predicted at zero pressure, for the entire range of alloy concentrations.The improved VCA correction is found to be essential in predicting the value of the band-gap bowing parameters. The electron effective masses of the Γ valley were also investigated. The agreement between our results and the available experimental data is generally satisfactory.Thus, the calculated EPM parameters can be incorporated into existing device simulators code to study nano-structured quantum dots and light-emitting diodes.