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Nano Research

Article Title

Highly regular rosette-shaped cathodoluminescence in GaN self-assembled nanodisks and nanorods

Authors

Bijun Zhao, Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra 0200, ACT, Australia
Mark Nicolas Lockrey, Australian National Fabrication Facility, Research School of Physics, The Australian National University, Canberra 0200, ACT, Australia
Naiyin Wang, Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra 0200, ACT, Australia
Philippe Caroff, Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra 0200, ACT, Australia
Xiaoming Yuan, Hunan Key Laboratory for Supermicrostructure and Ultrafast Process, School of Physics and Electronics, Central South University, 932 South Lushan Road, Changsha 410083, China
Li Li, Australian National Fabrication Facility, Research School of Physics, The Australian National University, Canberra 0200, ACT, Australia
Jennifer Wong-Leung, Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra 0200, ACT, Australia
Hark Hoe Tan, Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra 0200, ACT, Australia ARC Centre of Excellence for Transformative Meta-Optical Systems, Research School of Physics, The Australian National University, Canberra 0200, ACT, Australia Present address: Microstructural Analysis Unit, University of Technology Sydney, PO Box 123, Broadway, Sydney 2007, NSW, Australia Present address: Microsoft Quantum Lab Delft, Lorentzweg 1, CJ Delft 2628, Netherlands
Chennupati Jagadish, Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra 0200, ACT, Australia ARC Centre of Excellence for Transformative Meta-Optical Systems, Research School of Physics, The Australian National University, Canberra 0200, ACT, Australia Present address: Microstructural Analysis Unit, University of Technology Sydney, PO Box 123, Broadway, Sydney 2007, NSW, Australia Present address: Microsoft Quantum Lab Delft, Lorentzweg 1, CJ Delft 2628, Netherlands

Keywords

metalorganic chemical vapor deposition (MOCVD), GaN nanorod, cathodoluminescence, yellow luminescence, non-radiative recombination

Abstract

Self-assembled GaN nanorods were grown by metal-organic chemical vapor deposition. A highly regular rosette-shaped cathodoluminescence pattern in the GaN nanorods is observed, where its origin is helpful to deepen the understanding of GaN nanorod growth. The pattern forms at the very early stages of nanorod growth, which consists of yellow luminescence at the edges and the non-luminous region at six vertices of the hexagon. To clarify its origin, we carried out detailed cathodoluminescence studies, electron microscopy studies and nanoscale secondary ion mass spectrometry at both the nanorod surface and cross-section. We found the pattern is not related to optical resonance modes or polarity inversion, which are commonly reported in GaN nanostructures. After chemical composition and strain analysis, we found higher carbon and nitrogen cluster concentration and large compressive strain at the pattern area. The pattern formation may relate to facet preferential distribution of non-radiative recombination centers related to excess carbon/nitrogen. This work provides an insight into strain distribution and defect-related emission in GaN nanorod, which is critical for future optoelectronic applications.

Graphical Abstract

Publisher

Tsinghua University Press

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