1. Photoluminescence of double quantum wells: asymmetry and excitation laser wavelength effects
- Author
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Bravo-Velazquez, C. A., Lastras-Martinez, L. F, Ruiz-Cigarrillo, O., Flores-Rangel, G., Tapia-Rodriguez, L. E, Biermann, K., and Santos, P. V.
- Subjects
Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
Circularly polarized photoluminescence (PL) spectroscopy measured at 19 K on GaAs/AlGaAs symmetric and asymmetric double quantum wells (DQW) is reported. The PL is obtained by exciting the sample with a circularly polarized (left or right) laser in order to create an initial unbalanced distribution of electron spins in the conduction band and, in this way, obtain the electron spin lifetime $\tau_s$. The effects of the excitation laser wavelength were estimated by exciting with laser wavelengths of 701.0 nm, 787.0 nm, 801.5 nm and 806.5 nm. The increase of $\tau_s$ with the excitation wavelength is attributed to the lower initial quasi-momentum $\bf{k}$ of the excited carriers, which also reduces spin-orbit relaxation processes. $\tau_s$ was found to be higher in asymmetric DQWs: this is attributed to the wider QWs in these samples, which reduces spin relaxation due to the Dresselhaus mechanism. In addition, we also detected a smaller contribution from the Rashba mechanism by comparing samples with built-in electric fields of different orientations defined by doped barrier layers., Comment: 12 pages, 5 figures
- Published
- 2022
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