Atomic Structures and Chemical states of active and inactive dopants in GaN

We investigated atomic structures and chemical states of active and inactive dopant sites for Mg- and Si- doped in GaN using photoelectron holography and X-ray absorption near edge structure. In the case of Mg-doped GaN, we found that a Mg atom substituting a Ga atom (Mg Ga ) is an active dopant site in GaN whereas Mg Ga with two H atoms is an inactive dopant site in GaN. We found that a Si atom substituting a Ga atom is an active dopant site in Si-doped GaN whereas Si 3 N 4 is an inactive dopant site in GaN.