Parts | Days | Selection | Search | Updates | Downloads | Help
HL: Fachverband Halbleiterphysik
HL 25: Poster Session: GaN - Optical Properties & Preparation and Characterization & Devices
HL 25.18: Poster
Monday, March 26, 2012, 16:00–19:00, Poster D
Effect of growth parameters and annealing on the p-doping of GaN:Mg — •Gunnar Kusch, Martin Frentrup, Tim Kolbe, Tim Wernicke, Markus Pristovsek, and Michael Kneissl — Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, 10623 Berlin, Germany
One of the key challenges limiting the output power of group-III-nitride light emitting diodes (LEDs) and laser diodes is the p-doping of (Al)GaN with magnesium (Mg). During growth of GaN:Mg by metal-organic vapor phase epitaxy compensating defects are incorporated such as nitrogen vacancies, Mg-H-N complexes and inversion domains. The high activation energy is a further obstacle for effective p-doping with hole concentrations >1·1018 cm−3. We have investigated Mg incorporation in GaN in the range of 1019 to 1020 cm−3 as well as ex-situ activation and the influence of activation on LEDs. Variation of the Mg/III ratio showed a strong influence on the hole concentration. The lower limit is given by the n-type background doping below a II/III ratio of 15· 10−3 and the upper limit by compensating defects above a II/III ratio of 25· 10−3. The resulting growth window for p-doping is in good agreement with calculations and literature. Other growth parameters, such as V/III ratio, growth rate and growth temperature show lesser influence. Annealing studies at different temperatures show a lower limit for full activation at 600 ∘C.