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HL: Fachverband Halbleiterphysik

HL 81: Focus Session: Extended defects in semi- and nonpolar GaN II

HL 81.8: Talk

Thursday, March 14, 2013, 16:45–17:00, H13

Structural and luminescence properties of defects in silicon doped a-plane GaN — •Gordon Schmidt, Peter Veit, Frank Bertram, Sebastian Metzner, Silke Petzold, Matthias Wieneke, Armin Dadgar, Alois Krost, and Jürgen Christen — Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Germany

We present a correlation of the optical properties with the crystalline real structure of a silicon doped nonpolar GaN layer by means of highly spatially resolved cathodoluminescence spectroscopy (CL) performed in a scanning transmission electron microscope (STEM).

Using metal-organic vapor-phase epitaxy the structure was grown under a silane flow rate of 3.5 sccm on an r-plane sapphire substrate with an AlGaN seeding layer resulting in an a-plane GaN layer with a typically high basal plane stacking fault (BSF) as well as partial dislocation (PD) density.

The STEM-CL plan view images clearly resolve the BSF and their terminating PD at the surface of the nonpolar GaN layer. The comparison of the annular dark field images in STEM mode with the simultaneously recorded monochromatic CL intensity mappings directly identifies the BSF I₁ as the dominating emission. Furthermore, we observe a luminescence within 363 - 372 nm in the vicinity of the PD/BSF.