Tailoring of energy levels in strain-induced quantum dots

High-quality strain-induced quantum dots with properties that can be tailor ed have been fabricated by growing small InP islands on top of an InGaAs/Ga As near-surface quantum well. The quantum dots show small inhomogeneous bro adening, and peaks from the ground and excited state transitions are well r esolved in the photoluminescence spectra measured from the dots. The depth of the confining potential and the energy level separation can be varied ov er a relatively wide range from 35 meV to 100 meV and from 7 meV to 25 meV, respectively, by changing the top barrier thickness of the near-surface qu antum well and/or the size of the stressor islands.