OPTICAL STUDY OF BAND-EDGE BLUE-SHIFT IN ALGAN GAN DOUBLE-QUANTUM WELLS/

Optical properties of AlGaN/GaN double quantum wells grown by metalorg anic chemical vapor deposition are investigated. The wide-angle and sm all angle x-ray diffraction spectra show high crystalline quality of t he sample. Optical transmission and cathodoluminescence spectra exhibi t that there is a. blue shift of the energy bandedge in the AlGaN/GaN double quantum wells comparing to that of bulk GaN. The experimental d ata are compared to theoretical calculation based on the finite square well model and a confined particle transitions are identified. The ob served energy shift which differs from calculated values of ground sta te electron to heavy hole transition is attributed to strain in the Al GaN/CaN system.