Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 25: Poster Session: GaN - Optical Properties & Preparation and Characterization & Devices

HL 25.18: Poster

Montag, 26. März 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.