Optical studies on AlGaN/InGaN/GaN single quantum-well structures under external strains

Photoluminescence (PL) spectra from AlGaN/InGaN/GaN single quantum well str uctures with different In content in the InGaN well layer have been measure d with applying biaxial tensile stresses by a central-flexure method for th e purpose of studing piezoelectric-field effect on the well layer. The band -edge emission from the InGaN well layer showed linear variations against t he applied stress with different coefficients depending on the In content. We obtained. e.g., +17.5 meV/GPa for an InGaN layer with 20% In content. Ou r result presents a direct evidence for the presence of piezoelectric field which depends on the In content.