Strain effect on the band structure of InAs/GaAs quantum dots

The strain effect on the band structure of InAs/GaAs quantum dots has been investigated. 1 mu m thick InGaAs cap layer was added onto the InAs quantum dot layer to modify the strain in the quantum dots. The exciton energies o f InAs quantum dots before and after the relaxation of the cap layer were d etermined by photoluminescence. When the epilayer was lifted off from the s ubstrate by etching away the sacrifice layer (AlAs) by HF solution, the ene rgy of exciton in the quantum dots decreases due to band gap narrowing resu lted from the strain relaxation. This method can be used to obtain much lon ger emission wavelength from InAs quantum dots.