Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

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

HL 25.23: Poster

Montag, 26. März 2012, 16:00–19:00, Poster D

External oxidation of GaN studied by Perturbed Angular Correlations — •Michael Steffens¹, Reiner Vianden¹, and Alberto Pasquevich² — ¹Helmholtz-Institut für Strahlen- und Kernphysik, Universität of Bonn, Bonn, Germany — ²Departamento de Física, Facultad de Ciencias Exactas, UNLP, La Plata, Argentina

A sample of 7 µm GaN was heated in air at 1273 K in steps of 5 min for a total of 80 min. During this treatment, external oxidation of the sample occured. After each oxidation step, perturbed angular correlation measurements were performed at room temperature. The growth of the oxide will be discussed.

β-Ga₂O₃ can be used for transparent conductors or electronic devices. Thin films were already achieved with external oxidation, but the feasibility of these films for UV-photo diode production is largely reduced, possibly because of surface defects like oxygen vacancies [1].

The perturbed angular correlation (PAC) is an important tool to study point defects or lattice deformations in semiconductors. It is based on the hyperfine interaction between the intermediate state of a probe nucleus undergoing a γ-γ-cascade and an electric field gradient (EFG) generated by the electronic conditions in the sample. The strong dependence of the EFG to its origin makes PAC ideal for studies on the nanoscale.

[1] Weng et al., IEEE Sensors Journal, 11, 999 (2011)