We have studied influence of hydrostatic pressure on the light emission from cubic InGaN/GaN quantum wells (QWs) and cubic InGaN thick epilayers. A qualitative difference between pressure dependence of photoluminescence peak energies for cubic and wurtzite symmetry InGaN/GaN QWs was found. Cubic samples revealed magnitude of dEE/dP of 26-30 meV/GPa, practically independent of the QW width. Previous studies of the hexagonal InGaN/GaN structures showed a drastic drop of dEE/dP with increasing QW width. This different behavior of two types of QWs is explained by the lack of built-in electric field (along growth direction) in case of cubic structures. To describe pressure evolution of the optical transitions in cubic InGaN/GaN QWs, we use a simple k · p model based on the linear theory of elasticity. To reproduce the experimental data it is necessary to invoke presence of In-rich fluctuations in the studied samples. In contrast to QWs, thick epilayers of cubic InGaN exhibit the anomalously small dEE/dP. We suggest mechanisms causing likely this effect.
|Number of pages||5|
|Journal||Physica Status Solidi (B) Basic Research|
|Publication status||Published - 2002 Dec 1|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics