Full visible range emissions with ultra-high density InGaN/GaN quantum dots achieved by selective area growth

Abstract

In this study, we developed ultra-high density InGaN/GaN nanopyramid quantum dots (QD) via Selective Area Growth (SAG) using Metal–Organic Chemical Vapor Deposition (MOCVD). We achieved QDs as small as 23 nm-diameter QDs with a density of 7–10 × 10¹⁰ cm⁻². The optical and structural properties of these nanostructures were analyzed using Photoluminescence (PL), Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), and Transmission Electron Microscopy (TEM). Various growth conditions and structure designs including growth temperature, growth rate, TMIn flow rate, and InGaN thickness, were studied to extend the QD emission across the full visible emission range. Power-dependent and temperature-dependent PL measurements were conducted to further investigate the optical properties. An additional longer wavelength QD spectral emission peak was suppressed at low temperatures or higher excitation power, indicating the presence of Shockley-Read-Hall recombination at low injection carrier densities.