Carrier localization in the vicinity of dislocations in InGaN

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Massabuau, FCP 
Chen, P 
Horton, MK 
Rhode, SL 
Ren, CX 

We present a multi-microscopy study of dislocations in InGaN, whereby the same threading dislocation was observed under several microscopes (atomic force microscopy, scanning electron microscopy, cathodoluminescence imaging and spectroscopy, transmission electron microscopy), and its morphological optical and structural properties directly correlated. We achieved this across an ensemble of defects large enough to be statistically significant. Our results provide evidence that carrier localization occurs in the direct vicinity of the dislocation through the enhanced formation of In-N chains and atomic condensates, thus limiting non-radiative recombination of carriers at the dislocation core. We highlight that the localization properties in the vicinity of threading dislocations arise as a consequence of the strain field of the individual dislocation and the additional strain field building between interacting neighboring dislocations. Our study therefore suggests that careful strain and dislocation distribution engineering may further improve the resilience of InGaN-based devices to threading dislocations. Besides providing a new understanding of dislocations in InGaN, this paper presents a proof-of-concept for a methodology which is relevant to many problems in materials science.

40 Engineering, 4016 Materials Engineering
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Journal of Applied Physics
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American Institute of Physics
Engineering and Physical Sciences Research Council (EP/H019324/1)
Engineering and Physical Sciences Research Council (EP/I012591/1)
Engineering and Physical Sciences Research Council (EP/M010589/1)
Engineering and Physical Sciences Research Council (TS/G001383/1)
European Research Council (279361)
European Commission (312483)
This project is funded in part by the European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013)/ERC Grant Agreement No. 279361 (MACONS). The research leading to these results has received funding from the European Union Seventh Framework Programme under Grant Agreement 312483-ESTEEM2 (Integrated Infrastructure InitiativeI3). F.M. would also like to acknowledge the financial support from EPSRC Doctoral Prize Awards and Cambridge Philosophical Society. M.H. would like to acknowledge support from the Lindemann Fellowship.
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