Cu Induced Optical Transitions in MOCVD Grown Cu Doped GaN

Optical and structural properties of in situ Cu doped GaN thin films grown on sapphire substrates were optically investigated by means of Raman, photoluminescence (PL), and absorption spectroscopy. Different Cu concentrations in the films were analyzed by secondary ion mass spectroscopy (SIMS) and found to vary from 2×10 16 cm −3 to 5×10 17 cm −3 . Raman studies confirmed high crystalline quality of GaN:Cu with no major structural damages due to Cu incorporation. PL investigation revealed that the origin of the emission around 2.4 eV is most likely due to Cu incorporation. The electrical conductivity of the samples was analyzed by Hall measurements and the found semi-insulating behavior was assigned to the compensation of intrinsic donors by the deep Cu acceptor states.