High resolution x-ray diffraction, electron beam induced current, capacitance-voltage profiling, admittance spectroscopy, deep level transient spectroscopy (DLTS), microcathodoluminescence (MCL) spectra and imaging were performed for multi-quantum-well (MQW) GaN/InGaN p-n junctions grown on epitaxial laterally overgrown (ELOG) n-GaN platform layers. These experiments show a very good crystalline quality of the MQW ELOG GaN/InGaN structures with a dislocation density of ∼ 106 cm-2 in the laterally overgrown ELOG wings regions. Admittance and DLTS spectra show the presence of a prominent electron-trap signal with activation energy ∼0.4 eV likely originating from electron activation from the lowest occupied state in the quantum wells. MCL spectra clearly show a redshift of luminescence in the laterally grown ELOG wings compared to the normally grown ELOG windows. Modeling based on solving Poisson-Schroedinger equations suggests that the main reason for the observed redshift is a higher indium content in the wings.
ASJC Scopus subject areas
- Physics and Astronomy(all)