Transition metals as shallow donors in Ga2O3

We present an in-depth investigation of transition-metal impurities as shallow donors in monoclinic

Ga2O3 using first-principles calculations within the framework of density-functional theory (DFT). A

combination of semilocal and hybrid functionals is used to predict the binding energies and hyperfine

parameters. The generalized gradient approximation (GGA) allows performing calculations for

supercells of up to 2500 atoms, enabling extrapolation to the dilute limit. The shortcoming of GGA in

correctly describing carrier localization is then overcome by the use of the hybrid functional. Results

for Hf, Nb and W will be presented and discussed in light of the application of these transition-metal

elements as shallow donors in Ga2O3 and their identification in experiment. The methodology applied

here can be used in calculations for shallow donors in other systems.