3D structural construction of GaN-based light emitting diode by confocal micro-Raman spectroscopy

Abstract

The key issue for light emission strength of GaN-based LEDs is the high defect density and strain in MQWs causing the electric polarization fields. In this work, we construct 3D confocal microspectroscopy to clarify strain distribution and the relationship between photoluminescence (PL) intensity and pattern sapphire substrate (PSS). From 3D construction of E-2(high) Raman and PL mapping, the dislocation in MQW can be traced to the cone tip of PSS and the difference in E-2(high) Raman mapping between substrate and surface is also measured. The ability to measure strain change in 3D structure nondestructively can be applied to explore many structural problems of GaN-based optoelectronic devices.