Photoelectron Holographic Study of Atomic Structure of Si Dopants for Si-doped κ-Ga₂O₃(001)

We investigated the atomic sites occupancy for the Si dopants in Si-doped κ-Ga2O3(001) using photoelectron holography (PEH). From PEH, we found that three types of inequivalent Si substitutional sites (SiGa) were formed. The ratios for the tetrahedral, pentahedral, and octahedral SiGa sites were estimated to be 51%, 35%, and 14%, respectively. Higher (lower) ratios for the three inequivalent SiGa sites may come from lower (higher) formation energy. The tetrahedral (octahedral) SiGa site has the highest (lowest) ratio of the three SiGa sites since it has the lowest (highest) formation energy. We suggest that the tetrahedral SiGa site is due to the active dopant site, whereas the pentahedral and octahedral SiGa sites can be attributed to the inactive dopant sites for the Si-doped κ-Ga2O3(001).