Assessment of the Enhancement for the Excitation Emission in Porous Gan using Photoluminescence

Abstract

This work aims to assess the enhancement of optical properties for porous GaN nanostructures, which fabricated by Photoelectrochemical etching under different current densities. The changing of optical properties for different samples were investigated by Photoluminescence (PL) spectroscopy. A strong near band-gap-edge emission (NBE) was detected with peak energy 3.40 eV for as-grown and sample etched at 5mA/cm2, while its 3.41 and 3.42 eV for samples etched with 10 and 20mA/cm2 respectively. Also, another peak emission from the sapphire substrate at peak 1.7 eV was observed. The PL peak intensity of the porous samples have increased with increasing the porosity, while the FWHM of the near-band-edge peak was decreased in 5 and 10mA/cm2 samples compared to as-grown non-etched sample, indicated that the pore size decreased with etching current density and porosity. Finally, the change of refractive with porosity was investigated in the porous GaN nanostructure.

Precise Calculation of the Optical Constants of Self-standing Nanoporous Silicon Layers

“…This behavior is attributed to the different morphology and chemical composition of nanoPS layers grown under different fabrication parameters. This tendency is in agreement with the previously reported behavior of the optical constants of Al 2 O 3 and GaN porous layers, where a reduction in the index of refraction was observed with increasing porosity[18,19].…”