Eur. Phys. J. Plus (2016) 131: 195
https://doi.org/10.1140/epjp/i2016-16195-2

Regular Article

Correlation between structural and optical properties of GaN epi-layers by the cathodoluminescence technique

Research Unit: Physics of insulating and semi-insulating materials, Faculty of Sciences of Sfax, University of Sfax, Sfax, Tunisia

^* e-mail: f_bennasr@yahoo.fr

Received: 21 November 2015
Revised: 30 April 2016
Accepted: 9 May 2016
Published online: 14 June 2016

Abstract

Structural and optical properties of GaN epi-layers were investigated. The X-ray diffraction and the SEM observations show a predominant hexagonal structure with minor cubic GaN microcristallites. Experimental results of cathodoluminescence (CL) were reported at room temperature (RT) and low nitrogen temperature (LNT). CL signals show ultraviolet (UV) light emission arising from a large band gap (3 to 3.5eV), a yellow band (YB) around 2.2eV and a peak at 1.73eV due to porous silicon. Simulation CL profiles show good agreement with experimental results when we take into account the minor cubic phase contribution. Our attention was also focused on the study of the effects of temperature, electron beam energy, and residual strain on the individual CL signal from both h-GaN and c-GaN phases.