Characterization of InGaN/GaN Multiple Quantum Well Structures. Application to LEDs

InGaN/GaN Multi Quantum Well (MQW) structures were grown by MOCVD. For this study, various thicknesses of InGaN/GaN periods were investigated (from 90 to 130 Å) as well as the number of lattice periods (from 1 to 10). Transmission Electron Microscopy (TEM) revealed that the well/barrier interfaces are sharp. The (0002) High Resolution X-ray Diffraction (HRXRD) spectra show multiple satellite peaks due to interferences on well/barrier interfaces. We observed a very accurate correlation between the thickness deduced from X-ray spectra and TEM. All these observations prove that the InGaN/GaN interfaces are of high quality and well defined. The photoluminescence (300 K PL) peak intensity was shown to increase when the number of wells increases. Light Emitting Device (LED) structures have been grown following the above-mentioned model of MQW structures. Electroluminescence (EL) was performed on the devices and the results are in accordance with the material structures involved.