Influence of dislocations on indium diffusion in semi-polar InGaN/GaN heterostructures

Abstract

The spatial distribution of indium composition in InGaN/GaN heterostructure is a critical topic for modulating the wavelength of light emitting diodes. In this letter, semi-polar InGaN/GaN heterostructure stripes were fabricated on patterned GaN/Sapphire substrates by epitaxial lateral overgrowth (ELO), and the spatial distribution of indium composition in the InGaN layer was characterized by using cathodoluminescence. It is found that the indium composition is mainly controlled by the diffusion behaviors of metal atoms (In and Ga) on the surface. The diffusivity of metal atoms decreases sharply as migrating to the region with a high density of dislocations and other defects, which influences the distribution of indium composition evidently. Our work is beneficial for the understanding of ELO process and the further development of InGaN/GaN heterostructure based devices.

In Desorption in InGaN Nanowire Growth on Si Generates a Unique Light Emitter: From In-Rich InGaN to the Intermediate Core–Shell InGaN to Pure GaN

“…The four different growth regimes of NW formation are governed by the interplay of anisotropic In surface diffusion and In desorption on the m-plane NW sidewalls and the c-plane NW top as a function of the growth temperature, schematically drawn in Figure . In surface diffusion alone is considered because the In surface diffusion length is much larger than the Ga surface diffusion length. , In principle, there are two sources of In supply contributing to the axial NW growth: (i) Direct In deposition on the NW top, followed by surface diffusion and incorporation and (ii) In deposition between the NWs, followed by surface diffusion up the NW sidewalls to the top and incorporation . On the NW top, the In surface diffusion is toward the NW center as the junction between the c-plane top and m-plane sidewalls imposes an energy barrier for surface diffusion: There is no net surface diffusion from the NW top down the sidewalls, and the net surface diffusion on the NW sidewalls is up to the NW top, as indicated by the axial NW growth itself.…”

Multiwavelength Emission from InGaN/GaN MQW Truncated Pyramids Grown on a GaN Dodecagonal Pyramid Template

“…A theoretical model for the growth of InGaN/GaN MQWs on GaN templates using metal-organic chemical vapor deposition (MOCVD) is proposed. This model takes into account the combined effects of strain distribution at the InGaN/GaN heterostructure interface, different incorporation rates of Ga and In atoms at Ga- or N-polar surfaces, and different diffusion lengths of Ga and In adatoms on GaN template lateral facets, unlike previously published results that only consider one of these factors. , We will study all of the possibilities that induce indium inhomogeneity distribution. This work demonstrates a novel route to fabricate multiwavelength emission light-emitting diodes without phosphors by the regrowth of the InGaN/GaN MQWs on GaN dodecagonal pyramid templates.…”

Vapour Liquid Solid Growth Effects on InGaN Epilayers Composition Uniformity in Presence of Metal Droplets

“…Here we show that the presence of metal droplets on the surface, in addition to the already discussed effect on the growth rate [ 17 ], affects the incorporation of In in the InGaN epilayer and causes strong composition fluctuations. We demonstrate that this phenomenon is related to Vapor–Liquid–Solid (VLS) growth that takes place at the interface between the solid and the droplet [ 26 , 27 ].…”