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

Spectra of deep centers were studied in p-GaN(Mg) films prepared by metallo rganic 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 obser ved. Persistent photoconductivity measurements in p-GaN(Mg) films suggest t hat the phenomenon is very likely due to centers other than Mg. Studies of nonuniformity of recombination properties revealed the presence of high den sity of defects with characteristic dimensions of several microns for which the density of nonradiative recombination defects was lower than in the ma trix. It was also shown that the regions adjacent to pores in p-GaN films s how a higher luminescence intensity and a higher magnitude of the electron beam induced current. (C) 2001 Elsevier Science Ltd. All rights reserved.