First-principles study of n- and p-type doping opportunities in LiGaO₂

First-principles calculations are presented for Si, Ge, Sn doping of LiGaO₂. Both Si${}_{Ga}$ and Ge${}_{Ga}$ are found to be shallow donors. Sn${}_{Ga}$ is found to be a somewhat deeper donor. The site preference is studied and all three group-IV dopants are found to favor the Ga over the Li site when the Fermi level is in the upper part of the gap, corresponding to n-type doping and for Li-rich growth conditions. The prospects for n-type doping are thus favorable. N${}_O$ is found to be amphoteric with both deep donor and acceptor type transition levels. Zn has a significant site competition between Zn${}_{Li}$ (donor) and Zn${}_{Ga}$ (acceptor) levels, which would pin the Fermi level in the middle of the gap. Thus, p-type doping cannot be achieved with these dopants. (paper)