Growth and doping of bulk GaN by hydride vapor phase epitaxy

Zhang Yu-Min^{1, 2}, Wang Jian-Feng^{1, 2, †}, Cai De-Min², Ren Guo-Qiang¹, Xu Yu^{1, 2}, Wang Ming-Yue^{1, 2}, Hu Xiao-Jian^{1, 2}, Xu Ke^{1, 2, ‡}

Schematic diagram of the energy level of Fe³⁺ and Fe²⁺ in Fe-doped GaN.