Optical properties of InGaN/GaN double quantum wells with varying well thickness

• Published in: Solid state communications 2001-11, Vol.120 (12), p.509-514
• Main Authors: Ryu, Mee-Yi, Shim, Gyu Gwang, Yu, Phil Won, Oh, Eunsoon, Sone, Chulsoo, Nam, Okhyun, Park, Yongjo
• Format: Article
• Language: English
• Subjects: A. Quantum wells; A. Semiconductors; Condensed matter: electronic structure, electrical, magnetic, and optical properties; D. Optical properties; Exact sciences and technology; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Physics; Quantum wells
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/S0038-1098(01)00438-0

The optical properties and recombination kinetics of the InGaN/GaN double quantum well (DQW) structures with different well thickness (L w ) have been studied by means of photoluminescence (PL), time-resolved PL, and cathodoluminescence (CL) measurements. With increasing quantum well thickness up to 4 nm, the PL emission energy decreases and the blueshift of the PL emission energy increases with increasing excitation density. On the other hand, the PL emission energy of the DQWs with L w =16 nm is higher than that of the DQWs with L w =4 nm, and is independent of the excitation density. With increasing L w from 1 to 4 nm, the PL decay times increase. In contrast, the decay times of 16 nm DQWs are faster than those of 4 nm DQWs. These different results for 16 nm DQWs such as the blueshift of the emission energy, the decrease of the excitation density dependence, and the increase of recombination rate can be ascribed to the relaxation of the piezoelectric field. We also observed the inhomegeneity in the CL spectra of the DQWs with L w =1 nm on 1 μm scale.