Picture of virus under microscope

Research under the microscope...

The Strathprints institutional repository is a digital archive of University of Strathclyde research outputs.

Strathprints serves world leading Open Access research by the University of Strathclyde, including research by the Strathclyde Institute of Pharmacy and Biomedical Sciences (SIPBS), where research centres such as the Industrial Biotechnology Innovation Centre (IBioIC), the Cancer Research UK Formulation Unit, SeaBioTech and the Centre for Biophotonics are based.

Explore SIPBS research

Cross-sectional and plan-view cathodoluminescence of GaN partially coalesced above a nanocolumn array

Lethy, K. J. and Edwards, P. R. and Liu, C. and Wang, W. N. and Martin, R. W. (2012) Cross-sectional and plan-view cathodoluminescence of GaN partially coalesced above a nanocolumn array. Journal of Applied Physics, 112 (2). ISSN 0021-8979

[img]
Preview
PDF (Lethy et al., Journal of Applied Physics 112)
JAP_112_023507_lethy.pdf - Final Published Version

Download (2MB) | Preview

Abstract

The optical properties of GaN layers coalesced above an array of nanocolumns have important consequences for advanced optoelectronic devices. GaN nanocolumns coalesced using a nanoscale epitaxial overgrowth technique have been investigated by high resolution cathodoluminescence (CL) hyperspectral imaging. Plan-view microscopy reveals partially coalesced GaN layers with a sub-μm scale domain structure and distinct grain boundaries, which is mapped using CL spectroscopy showing high strain at the grain boundaries. Cross-sectional areas spanning the partially coalesced GaN and underlying nanocolumns are mapped using CL, revealing that the GaN bandedge peak shifts by about 25 meV across the partially coalesced layer of ∼2 μm thick. The GaN above the nanocolumns remains under tensile strain, probably due to Si out-diffusion from the mask or substrate. The cross-sectional data show how this strain is reduced towards the surface of the partially coalesced layer, possibly due to misalignment between adjacent partially coalesced regions. © 2012 American Institute of Physics