The electronic properties of multinary semiconductors often depend strongly on order/disorder effects on the cation sublattice. In its pure, stoichiometric, and fully ordered form, ZnSnN2 (ZTN) is a 1.4 eV gap semiconductor  with remarkable electronic properties similar to those of successful photovoltaic materials like CdTe or Cu(In,Ga)Se2. In practice, ZnSnN2 incorporates considerable amounts of oxygen, accommodates variable cation stoichiometries, and can exhibit various degrees of disorder. The computational task is to predict the photovoltaic properties of the real material as function of controllable process parameters. The optoelectronic properties of interest include band gap, effective masses, absorption coefficient, carrier localization, as well as the net doping. In order to obtain a comprehensive computational picture we calculate the non-equilibrium defect phase diagram, and perform Monte-Carlo simulations for oxygen containing, non-stoichiometric, and disordered ZTN.
 S. Lany et al., Phys. Rev. Mater. 1, 035401 (2017).