Dresden 2014 – wissenschaftliches Programm

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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 (ne) 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 ne. The recombination kinetics of the dominant CL show a monoexponential decay with initial lifetimes of the BSF I1 emission decreasing with higher ne 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.

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