Chris E. Kuklewicz, Ralph N. E. Malein, Pierre M. Petroff, Brian D. Gerardot
We investigate the effect of uniaxial stress on single particles in individual self-assembled InGaAs quantum dots embedded in a charge tunable device. Using a perturbative Coulomb blockade model, we distinguish the effect of external stress on the electron confinement, hole confinement, and Coulomb interaction energies. Under tensile stress, the single particle electron (hole) energy decreases (increases) significantly (~ 0.5 meV/MPa). Statistics reveal that the opposite slopes of the particle energy tunings lead to modest but widely variable exciton tuning (+40 to -2 micro-eV/MPa under tension), independent of the transition energy. This behaviour is ascribed to inherent structural differences between dots. The large change in the confinement energies affects the permanent dipole moment, resulting in tuning of the quantum confined Stark effect. Modest tuning of the Coulomb interaction and fine-structure splitting energies is also observed (~ 1 micro-eV/MPa). Finally, we exploit the variable response of different dots to strain to reversibly tune multiple independent quantum dots into resonance on the same chip.
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http://arxiv.org/abs/1204.4821
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