Localization and defects in axial (In,Ga)N/GaN nanowire heterostructures investigated by spatially-resolved luminescence spectroscopy

Abstract

(In,Ga)N insertions embedded in self-assembled GaN nanowires are of current interest for applications in solid state light emitters. Such structures exhibit a notoriously broad emission band. We use cathodoluminescence spectral imaging in a scanning electron microscope and micro-photoluminescence spectroscopy on single nanowires to learn more about the mechanisms underlying this emission. We observe a shift of the emission energy along the stack of six insertions within single nanowires that may be explained by compositional pulling. Our results also corroborate reports that the localization of carriers at potential fluctuations within the insertions plays a crucial role for the luminescence of these nanowire based emitters. Furthermore, we resolve contributions from both structural and point defects in our measurements.

arXiv comment10 pages, 7 figures

References in corpus (5)

• Direct experimental determination of the spontaneous polarization of GaN
• Self-regulated radius of spontaneously formed GaN nanowires in molecular beam epitaxy
• Coexistence of quantum-confined Stark effect and localized states in an (In,Ga)N/GaN nanowire heterostructure
• Visualising highly localised luminescence in GaN/AlN heterostructures in nanowires
• Correlation between In content and emission wavelength of InGaN/GaN nanowire heterostructures

Cited by in corpus (3)

• Radial Stark effect in (In,Ga)N nanowires
• Comparison of the luminous efficiency of Ga- and N-polar In${}_x$Ga${}_{1-x}$N/In${}_y$Ga${}_{1-y}$N quantum wells grown by plasma-assisted molecular beam epitaxy
• Ga-polar (In,Ga)N/GaN quantum wells vs. N-polar (In,Ga)N quantum disks in GaN nanowires: Comparative analysis of carrier recombination, diffusion, and radiative efficiency