Suppression of thermally excited electron-spin relaxation in InGaAs quantum dots using p-doped capping layers toward enhanced room-temperature spin polarization
Suppression of thermally excited electron-spin relaxation in InGaAs quantum dots using p-doped capping layers toward enhanced room-temperature spin polarization
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DOI：
10.1063/5.0004300
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发表时间：
2020-05
影响因子：
4
通讯作者：
Shino Sato;S. Hiura;J. Takayama;A. Murayama
中科院分区：
文献类型：
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作者：
Shino Sato;S. Hiura;J. Takayama;A. Murayama
利用时间分辨自旋相关光致发光测量了InGaAs量子点（QD）激发态的电子自旋极化，研究了p掺杂覆盖层对InGaAs量子点热激发电子自旋弛豫的抑制作用.我们发现，p型掺杂的量子点可以提高约2倍至3倍的QD-ES在很宽的温度范围内的发射强度。在293 K下观察到p型掺杂量子点的电子自旋弛豫时间为106 ps，相对于未掺杂量子点的71 ps的较短电子自旋弛豫时间，这比辐射寿命36 ps长约3倍。增加的电子自旋寿命主要归因于抑制弛豫的电子自旋reinjected从p型掺杂的盖帽势垒热逃逸后，从ES，其中的D 'yakonov-Perel'自旋弛豫的障碍是潜在的削弱通过杂质散射。这些结果表明，具有p掺杂的覆盖层的InGaAs量子点具有显著的优势，用于自旋功能光学有源层，具有朝向RT的更高的自旋极化。
The suppression of a thermally excited electron-spin relaxation in InGaAs quantum dots (QDs) using p-doped capping layers toward enhanced room-temperature (RT) spin polarization has been demonstrated, in which the electron-spin polarization in QD excited states (ESs) was measured through time-resolved spin-dependent photoluminescence. We revealed that the p-doping of QDs can enhance the emission intensity of QD-ES by approximately twofold to threefold over a wide temperature range. An electron-spin relaxation time of 106 ps was observed at 293 K for p-doped QDs, which is approximately three times longer than the radiative lifetime of 36 ps, relative to the shorter electron-spin relaxation time of 71 ps for undoped QDs. The increased electron-spin lifetime was mainly attributed to the suppressed relaxation of the electron spin reinjected from the p-doped capping barrier after thermal escape from an ES, where the D'yakonov-Perel' spin relaxation in the barrier was potentially weakened through impurity scattering. These results suggest that InGaAs QDs with p-doped capping layers have a significant advantage for use in spin-functional optical active layers with a higher spin polarization toward RT.