Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 5: Nitrides: mostly transport properties and recombination processes

HL 5.1: Talk

Monday, March 31, 2014, 09:30–09:45, POT 251

Non-radiative recombination mechanisms in GaN by first-principles total energy calculations — •Ying Cui, Christoph Freysoldt, and Jörg Neugebauer — Max-Planck-Institut für Eisenforschung, Max-Planck-Str. 1, 40627 Düsseldorf

Non-radiative recombination limits the efficiency of GaN based LEDs. However, the chemical nature and atomic geometry of the recombination centers and their recombination cross-sections are generally not known. Employing a Shockley-Read-Hall model, we propose a one-dimensional (1-D) model to locate the transition state in the capture process using the defect level occupation as a natural reaction coordinate. The calculations are based on density functional theory with hybrid functional (HSE). Employing this approach, we obtain the electron (hole) capture cross-sections, which can be directly compared with experimental results, such as deep-level transient spectroscopy(DLTS). Among all the defects in our study, nitrogen vacancies show the largest potential to be effective non-radiative recombination centers. Their calculated activation energy and electron capture cross-sections agree well with experimental data reported in literature.