Dresden 2006 – scientific programme
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HL: Halbleiterphysik
HL 9: Poster I
HL 9.45: Poster
Monday, March 27, 2006, 15:15–17:45, P3
PAC-measurements in GaN on alternative Si(111)-based substrates — •J. Penner1, R. Vianden1, A. Dadgar2, and A. Krost2 — 1Helmholtz - Institut für Strahlen- und Kernphysik der Universität Bonn, Nußallee 14-16, 53115 Bonn, Germany — 2Institut für Experimentelle Physik, Otto-von-Guericke-Universität, PO-Box 4120, 39016 Magdeburg, Germany
Si(111) substrates are an interesting alternative for growing GaN epilayers. However, since lattice parameters and thermal behaviour of Si differ from GaN, high defect densities and hydrostatic expansion is produced during the growth of epilayers. Thin AlN buffer layers can help to build up compressive strain and to reduce the defect density [1]. The AlN layers also passivate the silicon surface and inhibit the so-called melt-back etching. We used the Perturbed-Angular-Correlation (PAC) method to study the electric field gradient at the site of 111In implanted into GaN/AlN/Si(111). Subsequently, an annealing programme was carried out. A similar behaviour as seen in GaN grown on sapphire is found.However, the interaction frequency observed for probes on regular sites and the frequency for probes sitting in an disturbed environment are significantly higher than the corresponding values for GaN/sapphire. We discuss possible reasons for this behaviour.
[1] A. Dadgar et. al.; Appl. Phys. Lett. 82 (2003), 28-30