Trends in opto-electronic properties of MgxZn1-xSnN2 using first principles methods

Abstract

We have computationally studied MgxZn1-xSnN2 alloy system in wurtzite structure using density functional theory and beyond. Cationic disorder of the random limit is chosen for modeling the crystal structure. Lattice mismatch of less than 1 % in the alloy system helps in the miscibility of Mg and Zn, thus making it widely useful in tandem solar cells. Electronic band gaps increase linearly with higher Mg concentration. These materials have hole effective masses significantly lower than electron effective masses. Considerable absorption together with a lower reflectivity can render this alloy an effective absorber. All the alloys are mechanically stable, but (x=0.25) and (x=0.50) are dynamically unstable. These alloys also exhibit large hardness.