Role of open volume defects in Mg-doped GaN films studied by positron annihilation spectroscopy
- 3 October 2005
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 72 (16), 165303
- https://doi.org/10.1103/physrevb.72.165303
Abstract
We have performed a systematic study by positron annihilation spectroscopy of magnesium-doped, codoped, and annealed GaN films made by metal organic chemical vapor deposition. GaN:Mg films are free of detectable vacancy defects up to , but at doping levels above vacancies are observed. Two defects are identified: pairs and vacancy clusters, where the amount of the missing atoms is estimated to be about 60. The defects have an inhomogeneous depth profile with a layer of higher defect concentration starting below the surface. Thermal annealing dissociates the pairs and the vacancy clusters, which migrate and form a homogeneous distribution of smaller clusters through the film. The identified defects play an important role in the electrical compensation and activation of the Mg acceptors in GaN films, and show correlations with results from transmission electron microscopy and photoluminescence studies.
Keywords
This publication has 35 references indexed in Scilit:
- N vacancy diffusion and trapping in Mg-doped wurtzite GaNJournal of Applied Physics, 2004
- Diffusivity of native defects in GaNPhysical Review B, 2004
- Vacancy Defects as Compensating Centers in Mg-Doped GaNPhysical Review Letters, 2003
- Mg-O anddefect complexes in cubic GaNPhysical Review B, 2000
- Mg-doped GaN: Similar defects in bulk crystals and layers grown on Al2O3 by metal–organic chemical-vapor depositionApplied Physics Letters, 1999
- Spontaneous Ordering in Bulk GaN:Mg SamplesPhysical Review Letters, 1999
- Positron Annihilation in SemiconductorsPublished by Springer Science and Business Media LLC ,1999
- Nature of the 2.8 eV photoluminescence band in Mg doped GaNApplied Physics Letters, 1998
- Thermal Annealing Effects on P-Type Mg-Doped GaN FilmsJapanese Journal of Applied Physics, 1992
- P-Type Conduction in Mg-Doped GaN Treated with Low-Energy Electron Beam Irradiation (LEEBI)Japanese Journal of Applied Physics, 1989