Carrier Diffusion in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:mrow><mml:mi>Ga</mml:mi><mml:mi mathvariant="normal">N</mml:mi></mml:mrow></mml:math> : A Cathodoluminescence Study. III. Nature of Nonradiative Recombination at Threading Dislocations

We investigate the impact of threading dislocations with an edge component ($a$ or $a+c$ type) on carrier recombination and diffusion in $\mathrm{Ga}\mathrm{N}$(0001) layers close to surface as well bulk. To this end, we utilize cathodoluminescence imaging top a layer deeply buried (In,$\mathrm{Ga}$)N quantum well. Varying acceleration voltage primary electrons comparing signal from enables us probe at depths ranging vicinity position Our experiments are accompanied by fully three-dimensional Monte Carlo simulations drift, diffusion, presence surface, well, dislocation, taking into account dislocation strain field resulting piezoelectric outcrop. Near establishes exciton dead zone around extent which is not related length. However, reliable values length can be extracted dipolelike energy shift observed hyperspectral maps recorded outcrop low voltages. For high voltages, allowing depth where unaffected effects, observe much stronger contrast than expected alone. This finding provides unambiguous experimental evidence for strong nonradiative activity bulk $\mathrm{Ga}\mathrm{N}$ hence also heterostructures.