Electrical and optical properties of GaN films implanted with Mn and Co

Optical transmission spectra, microcathodoluminescence spectra, capacitance-voltage and capacitance-frequency curves, temperature dependence of resistivity and deep level spectra with both electrical and optical injection were measured on n-GaN samples implanted with high doses of Mn (3x10(16) and 4x10(16) cm(-2)) and Co (4x10(16) cm(-2)). From optical transmission it was found that Mn forms a deep acceptor near Ev+1.8 eV while the Co acceptor is about 0.1 eV deeper. In addition, Mn and Co form complexes with native defects and these complexes are deep electron traps with a level near Ec-0.5 eV. Such complexes are most likely responsible for a strong blue luminescence band with energy near 2.9 eV. Adjacent to the implanted region a defect region about 1 mum deep is formed, most likely by out-diffusion of point defects from the implanted zone during the 700 degreesC annealing used to partially remove the radiation damage. This region is characterized by a high density of electron traps at Ec-0.25 eV and Ec-0.7 eV and hole traps at Ev+0.2 eV, Ev+0.35 eV and Ev+0.45 eV. (C) 2002 American Institute of Physics.