Optical properties of the deep Mn acceptor in GaN:Mn

Abstract

The optical and electrical properties of Mn-doped epitaxial GaN were studied. Low-temperature optical absorption measurements indicate the presence of a Mn-related band with a well-resolved fine structure. The zero-phonon line is at 1.418±0.002 eV with a full width at half maximum of 20±1 meV. Two pseudolocal vibrational modes associated with manganese were observed with energies of hv1=20 and hv2=73 meV. Deep-level optical spectroscopy measurements on lightly Mn-doped samples indicate that Mn forms a deep acceptor level at Ev+1.42 eV. Using the vacuum referred binding energy model for transition metals and the measured Mn energy level, the electron affinity of GaN is calculated to be 3.4 eV, which agrees well with experimental values.