Carrier localization in the vicinity of dislocations in InGaN

Massabuau, F. C-P. and Chen, P. and Horton, M. K. and Rhode, S. L. and Ren, C. X. and O'Hanlon, T. J. and Kovács, A. and Kappers, M. J. and Humphreys, C. J. and Dunin-Borkowski, R. E. and Oliver, R. A. (2017) Carrier localization in the vicinity of dislocations in InGaN. Journal of Applied Physics, 121 (1). 013104. ISSN 0021-8979

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    Abstract

    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.