Deep centers spectra and scanning electron microscope studies of p-GaN films prepared by metallorganic chemical vapor deposition on sapphire

Abstract Spectra of deep centers were studied in p-GaN(Mg) films prepared by metallorganic chemical vapor deposition on sapphire. In addition to the E v +0.16 eV Mg acceptor levels hole traps with a level near E v +0.4 eV were observed. Persistent photoconductivity measurements in p-GaN(Mg) films suggest that the phenomenon is very likely due to centers other than Mg. Studies of nonuniformity of recombination properties revealed the presence of high density of defects with characteristic dimensions of several microns for which the density of nonradiative recombination defects was lower than in the matrix. It was also shown that the regions adjacent to pores in p-GaN films show a higher luminescence intensity and a higher magnitude of the electron beam induced current.