Simulated Structural and Electronic Properties of Cation-Disordered ZnGeN2 and its Interface with GaN

Cation disorder is increasingly being studied as a means of tuning properties in electronic materials. Through Monte Carlo simulations and first-principles calculations, we determine the ranges of elastic moduli and polarization constants in ZnGeN₂ as a function of ordering. We use heterostructure calculations to demonstrate a disorder-dependent type-I or type-II band offset between relaxed GaN and strained ZnGeN₂ in the polar [001] direction. Modeling polarization and band offsets, we then use these calculations to comment on which values are desirable for device design, which parameters are obtainable through targeted growth techniques, and the challenges that remain in realizing a device and understanding cation disorder in heterostructures. Although the elastic and polarization properties change little with the order parameter, the band characteristics undergo dramatic shifts, creating a type-I band offset in partially disordered material.