Matrix dependence of strain-induced wavelength shift in self-assembled InAs quantum-dot heterostructures

We report on the matrix-dependent strain effect in self-assembled InAs quan tum-dot heterostructures using photoluminescence measurements. A series of samples were prepared to examine the effect of quantum dot position with re spect to the so-called strain-reducing layer (SRL). Since the SRL reduces t he residual hydrostatic strain in the quantum dots, long emission wavelengt h of 1.34 mu m is observed for the InAs quantum dots with an In0.16Ga0.84As SRL. The dependence of the emission wavelength on the thickness of the cap layer on SRL also indicates the importance of the role of matrix in the st rain relaxation process of the dots. Using In0.16Al0.84As instead of In0.16 Ga0.84As as the SRL, a blueshift in wavelength is observed because the elas tic stiffness of In0.16Al0.84As is higher than that of In0.16Ga0.84As and l ess strain is removed from the dots with In0.16Al0.84As SRL. (C) 2000 Ameri can Institute of Physics. [S0003-6951(00)00112-1].