Influence of InGaN Quantum Disk Thickness on the Optical Properties of GaN Nanowires

The optical emission properties of axial InGaN/GaN nanowires with different InGaN quantum disk (Qdisk) thicknesses are experimentally investigated using a combination of photoluminescence (PL) and cathodoluminescence (CL) spectroscopy. Both the spectroscopic measurements from the average InGaN Qdisk-related emissions reveal the presence of built-in piezoelectric strain as evidenced by the luminescence blueshift with increasing pump signal. To determine the material compositions and their spatial uniformity, transmission electron microscopy with energy-dispersive x-ray spectroscopy were also performed. Systematic analysis of the optical emission properties with the change of Qdisk thickness serves to advance the understanding of, in general, III-nitride nanostructures for the implementation of classical and non-classical optoelectronic devices.