Photo-Enhanced Activation of Hydrogen-Passivated Magnesium in P-Type GaN Films

We studied the effect of UV-light irradiation on annealing of as-grown Mg-doped GaN films by resistivity and Hall measurements. The annealing temperature where the resistivity reduction due to the electrical activation of hydrogen-passivated Mg occurred with the increase of hole density and the decrease of hole mobility, was reduced from 550 to 450°C by the irradiation of UV light with a peak wavelength around 350 nm. This suggests that electronic excitation reduces the thermal stability of Mg-H complexes in GaN.