9 February 2007 Charging and spin-polarization effects in InAs quantum dots under bipolar carrier injection
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An ultrafast pump-probe method based on differing polarization properties of neutral and charged excitons in semiconductor quantum dots (QDs) is employed to study carrier dynamics in InGaAs QDs grown in nominally undoped, modulation doped and p-i-n structures. We find that at low temperature even in the nominally undoped samples there are large fractions of charged dots. It is also demonstrated that for bipolar electrical injection there is a high probability of the independent capture of electrons or holes into the dots, resulting in dot charging. Voltage-control of the charged exciton population, created via a combination of electrical and optical excitation, which exhibits a long lived spin-polarization (or spin-memory) is demonstrated.
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A. I. Tartakovskii, A. I. Tartakovskii, A. V. Savelyev, A. V. Savelyev, M. N. Makhonin, M. N. Makhonin, M. S. Skolnick, M. S. Skolnick, D. J. Mowbray, D. J. Mowbray, M. V. Maximov, M. V. Maximov, V. M. Ustinov, V. M. Ustinov, R. P. Seisyan, R. P. Seisyan, "Charging and spin-polarization effects in InAs quantum dots under bipolar carrier injection", Proc. SPIE 6471, Ultrafast Phenomena in Semiconductors and Nanostructure Materials XI and Semiconductor Photodetectors IV, 64710J (9 February 2007); doi: 10.1117/12.697151; https://doi.org/10.1117/12.697151

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