Abstract
We have studied the low-temperature (T=6 K) optical properties of a series of InGaNGaN single-quantum-well structures with varying indium fractions. With increasing indium fraction the peak emission moves to lower energy and the strength of the exciton-longitudinal-optical (LO)-phonon coupling increases. The Huang-Rhys factor extracted from the Fabry-Ṕrot interference-free photoluminescence spectra has been compared with the results of a model calculation, yielding a value of approximately 2 nm for the in-plane localization length scale of carriers. We have found reasonable agreement between this length scale and the in-plane extent of well-width fluctuations observed in scanning transmission electron microscopy high-angle annular dark-field images. High-resolution transmission electron microscopy images taken with a short exposure time and a low electron flux have not revealed any evidence of gross indium fluctuations within our InGaN quantum wells. These images could not, however, rule out the possible existence of small-scale indium fluctuations, of the order of a few at. %. © 2005 American Institute of Physics.
| Original language | English |
|---|---|
| Article number | 103508 |
| Journal | Journal of Applied Physics |
| Volume | 97 |
| Issue number | 10 |
| Early online date | 29 Apr 2005 |
| DOIs | |
| Publication status | Published - 15 May 2005 |
Keywords
- LO phonon (coupling; optical and microstructural studies of InGaN/GaN single-quantum-well structures); Exciton (exciton recombination lifetime in InGaN/GaN single-quantum-well structures); Exciton luminescence (exciton-phonon; of InGaN/GaN single-quantum-well structures); Surface structure (of InGaN/GaN single-quantum-well structures); Microstructure; Quantum well devices (optical and microstructural studies of InGaN/GaN single-quantum-well structures)