Scanning Electron Microscopy Cathodoluminescence Studies of Piezoelectric Fields in an InGaN Multiple Quantum Well Light-Emitting Diode

Scanning Electron Microscopy (SEM)-based Cathodoluminescence (CL) experiments were used to study the influence of piezoelectric fields on the optical and electrical properties of a commercial InGaN-based Multiple Quantum Well (MQW) Light Emitting Diode (LED). The existence and direction of a piezoelectric field in the InGaN-based LED was determined with voltage dependent SEM-CL experiments. The CL emission peak showed a blueshift followed by a redshift with increasing reverse bias due to the full compensation of the piezoelectric field. It was determined that the piezoelectric field points in the [000-1] direction and the magnitude was estimated to be approximately 1.0±0.2 MV/cm. SEM-CL carrier generation density variation and electroluminescence experiments were used to confirm the existence of a piezoelectric field in the InGaN-based MQW LED.