Analysis of ion irradiations and wet etching of gallium nitride epilayers grown by hype and mocvd techniques

Abstract

Ion beam irradiations and etching techniques are commonly used to understand material properties and to investigate defect formation. Understanding defect mechanics, strain and bandgap engineering is crucial for device fabrication. Irradiation damage can alter Gallium Nitride (GaN) electrical properties, such as carrier density, resistivity and mobility, necessitating non-invasive optimization techniques in electronic and optoelectronic device design. In addition, the study of GaN etching provides valuable insights into defects, crystal structure and electrical properties. These advancements have paved the way for using GaN in various fields.This study explains about the light and heavy ion irradiation and wet etching effect on GaN epilayers grown by Hydried Vapour Phase Epitaxy (HVPE) and Metalorgano Chemical Vapour Deposition (MOCVD) methods. The goal is to understand the defect formation and its impact on the structural, electrical and optical properties of GaN. The HVPE grown GaN epilayer was irradiated with light ion of 100 MeV O7+ ions at different fluence using 15 MV pelletron at IUAC New Delhi. The X-ray Diffraction (XRD) analysis confirmed the wurtzite structure of the as-grown and irradiated epilayers. Scanning Electron Microscopy (SEM) images provided the epilayer thickness and Atomic Force Microscopy (AFM) revealed the increased roughness with higher irradiation fluence. The effects of irradiation were further investigated using micro-Raman and Photoluminescence (PL) spectroscopies. The micro-Raman spectrum was fitted using the Lorentz method showing a decrease in the area under the curve for and A1(LO) modes with increasing fluence. newline