论文标题
双量子井的光致发光：不对称和激发激光波长效应
Photoluminescence of double quantum wells: asymmetry and excitation laser wavelength effects
论文作者
论文摘要
据报道，在GAAS/ALGAAS对称和非对称双量子井（DQW）上，在19 K上测得的圆形极化光致发光（PL）光谱法。 PL是通过用圆形极化（左或右）激光刺激样品获得的，以创建传导带中电子旋转的初始不平衡分布，并通过这种方式获得电子自旋寿命$τ_s$。激发激光波长的效果通过激光波长为701.0 nm，787.0 nm，801.5 nm和806.5 nm来估计。随着激发波长的增加$τ_s$的增加归因于激发载体的较低初始Quasi-momentum $ \ bf {k} $，这也减少了旋转轨道放松过程。 $τ_s$在不对称的DQW中发现较高：这归因于这些样品中较宽的QW，这会减少由于Dresselhaus机制而引起的旋转放松。此外，我们还通过将样品与掺杂屏障层定义的不同方向的内置电场进行比较，从RASHBA机制中检测到了较小的贡献。
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 $τ_s$. 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 $τ_s$ 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. $τ_s$ 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.
