Study of lattice properties of Ga1−x Mnx N epilayers grown by plasma-assisted molecular beam epitaxy by means of optical techniques

Raman spectroscopy has been used to study the lattice properties of plasma-assisted molecular beam epitaxy grown GaN:Mn layers (0-18% Mn). Raman spectra corresponding to the intrinsic GaN layers demonstrate three Raman active excitations at 144, 570 and 729.2 cm−1, identified as E2L, E2H and A1(LO) respectively. The Mn-doped GaN layers exhibit additional excitations attributed to defect-activated Raman scattering and Mnm-N (m =1-4) related frequency modes in the vicinity of E2H mode. Subsequently, detailed X-ray diffraction measurements have revealed the coexistence of cubic phases in the predominantly hexagonal GaN lattice.