The dependence of Raman scattering on Mg concentration in Mg-doped GaN grown by MBE

Magnesium-doped GaN (GaN:Mg) films having Mg concentrations in the range 5 × 1018–5 × 1020 cm−3 were fabricated by molecular beam epitaxy. Raman spectroscopy was employed to study the effects of Mg incorporation on the positions of the E2 and A1(LO) lines identifiable in the Raman spectra. For Mg concentrations in excess of 2 × 1019 cm−3, increases in the Mg concentration shift both lines to higher wave numbers. The shifts of the Raman lines reveal a trend towards compressive stress induced by incorporation of Mg into the GaN films. The observed correlation between the Mg concentration and the Raman line positions establish Raman spectroscopy as a useful tool for optimizing growth of Mg-doped GaN.