Hole trap levels in Mg-doped GaN grown by metalorganic vapor phase epitaxy

Hole trap levels in a Mg-doped GaN grown by metalorganic vapor phase epitaxy (MOVPE) are studied with deep level transient spectroscopy (DLTS). The Mg concentration of the sample was ${\text{4.8×10}}^{19}\hspace{0.17em}{\mathrm{cm}}^{\mathrm{-3}},$ but the hole concentration was as low as ${\text{1.3×10}}^{17}\hspace{0.17em}{\mathrm{cm}}^{\mathrm{-3}}$ at room temperature. The DLTS spectrum has a dominant peak $D_1$ with activation energy of $\text{0.41±0.05\hspace{0.17em}}\mathrm{eV},$ accompanied by two additional peaks with activation energies of $\text{0.49±0.09\hspace{0.17em}}\mathrm{eV}{\mathrm{(D}}_2)$ and $\text{0.59±0.05\hspace{0.17em}}\mathrm{eV}{\mathrm{(D}}_3\mathrm{).}$ It was found that the dominant peak $D_1$ consists of five peaks, each of which has different activation energy and capture cross section. A relevant model for these levels is presented in relation to the Mg–N–H complexes.