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HL: Fachverband Halbleiterphysik

HL 53: Nitrides: Preparation of nonpolar and semipolar orientations

HL 53.2: Vortrag

Dienstag, 1. April 2014, 14:15–14:30, POT 151

The impact of silicon doping on the optical properties of the stacking fault emission in a-plane GaN — •Gordon Schmidt, Christopher Karbaum, Sebastian Metzner, Frank Bertram, Peter Veit, Matthias Wieneke, Hartmut Witte, Armin Dadgar, Martin Feneberg, Rüdiger Goldhahn, Alois Krost, and Jürgen Christen — Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Germany

In GaN the basal plane stacking fault (BSF) type I₁ is a two dimensional defect characterized by a cubic inclusion within the wurtzite structure. Excitons are bound at the BSF I₁ similar to the localization in a quantum well heterostructure leading to an efficient radiative recombination.

We present a study of the BSF I₁ emission from a-plane GaN layers with a systematic variation of the silicon doping level. Using metal-organic vapor phase epitaxy the a-plane GaN layers were grown on r-plane sapphire substrates with an AlGaN seeding layer. Varying the silane flow rate the electron concentration (n_e) was changed between nominally undoped and 3·10¹⁹ cm⁻³.

In cathodoluminescence (CL) experiments at 5 K the BSF I₁ emission is the most intense recombination whose peak energy exhibits a strong blueshift from 3.423 eV to 3.473 eV with increasing n_e. The recombination kinetics of the dominant CL show a monoexponential decay with initial lifetimes of the BSF I₁ emission decreasing with higher n_e from 2.9 ns to 470 ps. Our results will be discussed in terms of reduction of the quantum confined Stark effect within the BSF I₁.