Localization effect and optical properties of InGaN/GaN Multiple-Quantum-Wells Nanopillars

Abstract

Temperature and excitation-power dependent photoluminescence (PL) have been carried out on InGaN/GaN multiple-quantum-wells (MQWs) nanopillars with average diameters of 100 nm and 160 nm, respectively. ‘S-shaped’ temperature dependent PL peak positions have been quantitatively simulated and analyzed with the localized-state ensemble luminescence model. It is found that after nanotexturing both localization effect and quantum confinement Stark effect (QCSE) are weakened, and the smaller the pillars are the weaker the two effects. The argument is further evidenced by the micro-Raman scattering measurements. Cathodoluminescence (CL) spectrum and panchromatic CL image have been also employed to study the newly induced carrier recombination pathways on the sidewalls of the nanopillars.