Evaluation of dislocation-related defects in GaN using deep-level transient spectroscopy

A method to extract the carrier capture kinetics of traps in the neutral region by isothermal deep-leveltransient spectroscopy using two sets of bias pulses was applied to the traps with similar energy levels around E-c-0.6 eV in GaN grown by metalorganic chemical vapor deposition on GaN and sapphire substrates. The E-c-0.6 eV trap in GaN on GaN is found to be the isolated point defects. The E-c-0.6 eV trap in GaN on sapphire shows the logarithmic capture kinetics, expected for dislocation-related defects. This is ascribed to the difference in dislocation density between GaN on GaN and sapphire substrates. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.