Metalorganic chemical vapor deposition and structural/optical characteristics of InGaN/GaN multiple quantum wells grown on sapphire for light emitting diode application

Abstract

InGaN/GaN Multiple Quantum Well (MQW) structures have been grown on sapphire substrates by low pressure metalorganic chemical vapor deposition (MOCVD), for wide range of blue, blue-green and green light emission device application. The compositions and sizes within QWs were designed according to the requirements on the LED performance. Samples were investigated by a variety of characterization techniques. Optimization of the growth parameters and process was realized and evidenced by high resolution X-ray diffraction (XRD) measurements. High quality of MQW wafers have been achieved with excellent characteristics, showing XRD multiple satellite peaks up to 10 th order due to the quantum well superlattice confinements and fine fringe structures among satellite peaks. Transmission electron microscopy confirmed the sharp MQW structures and dimensional parameters, and revealed the V-shape defects. Optical properties were further studied and Quantum confined Stokes effect was observed from photoluminescence and photoluminescence excitation measurements.