PHOTOLUMINESCENCE STUDY OF STRAIN-INDUCED QUANTUM-WELL DOTS BY WET-ETCHING TECHNIQUE

Simple holographic lithography and wet etching have been used to fabricate strain-induced quantum well dot structures. Lateral confinement was generated in a GaAs quantum well (QW) by etching a double-exposed grating pattern into a pseudomorphic, strained layer of In0.3Ga0.7As which overlies the QW. By spacing three QWs of different widths at varying depth from the stressor, lateral strain confinement and vertical strain propagation are directly resolved. We have observed at 14 meV redshift in the photoluminescence spectra for the QW located 22 nm away from the stressors and have confirmed that the strain propagation depth along the material growth direction is comparable to the lateral dot dimension.