Structure and gap of low-x (Ga1-xInx)(2)O-3 alloys

We study the electronic and local structural properties of pure and In-substituted beta-Ga2O3 using density functional theory. Our main result is that the structural energetics of In in Ga2O3 causes most sites to be essentially inaccessible to In substitution, thus limiting the maximum In content to somewhere between 12 and 25 % in this phase. We also find that the band gap variation with doping is essentially due to \"chemical pressure\", i.e. volume variations with doping.