First-principles predictions of the physical properties of GaNxAs1–x: Materials for futuristic optoelectronic devices

Knowledge of the physical properties of a material is crucial to realising its practical technological applications. In this regard, a study related to phase stability, transition pressure, electronic properties, optical properties, and thermal properties of GaAs, GaN, as well as their mixed ternary alloys GaN0.25As0.75, GaN0.5As0.5 and GaN0.75As0.25 is presented. The study is performed by employing a “full-potential-linearized augmented plane wave plus local-orbital (FP-L(APW + lo)) approach framed within the density functional theory (DFT)” and recognized within WIEN2k computational code. The results of the phase stability show that the GaNxAs1–x alloys are stable for all compositions in the zinc blende phase (B3), except for x = 1, whereas the structure corresponding to the x = 1 composition is found to be more stable in the wurtzite (B4) phase. The physical properties of the more stable phases corresponding to each composition are explored. The pressure-induced phase transition is also investigated, corresponding to each composition. The electronic and optical properties are investigated using the “Tran–Blaha modified Becke–Johnson (mBJ)” potential approach. To explore the thermal properties, the "quasi-harmonic Debye model" approach is employed. Our calculated results of the absorption coefficients and optical band gap show that these alloys could be appropriate candidates for applications in solar cells and optoelectronic devices.