Revealing the stability and optoelectronic properties of novel nitride and phosphide semiconductors: A DFT prediction

Nitride semiconductors have attracted considerable attention in recent years. CaZn2N2 and SrZn2N2 are the promising materials for optoelectronic applications. In order to explore more novel semiconductors, a detailed theoretical study has been performed to investigate the structural, electronic, and optical properties of AB2×2 (A = Ca, Sr, Ba; B = Mg, Zn, Cd; X = N, P) and their alloys. The calculated band gaps of nitride compounds with the HSE06 functional are consistent well with the reported experimental values. Most compounds are direct bandgap semiconductors and they show tunable band gaps. Nine compounds show suitable direct band gaps with the values of 1.4–1.8 eV. In addition, the stability of four alloying compounds is confirmed by different theoretical methods. Moreover, these phosphide compounds and their alloys also show good carrier mobility. Importantly, Sr(Zn0.5Cd0.5)2P2 contains less toxic Cd element, and it has an ideal band gap of 1.38 eV and high absorption coefficient, which is the most promising material for optoelectronic applications. The present study has indicated the potential suitability of phosphide semiconductors for solar cell applications.