Myoung Soung, Mun Ok Mi, Yim Sang-Youp, Kim Jong Su
J Nanosci Nanotechnol. 2015 Nov;15(11):8684-7. doi: 10.1166/jnn.2015.11484.
This work is focused on spectroscopically characterizing kinetic properties of concentric quantum-ring complexes of GaAs quantum dots. Quantum-ring (or double-ring) GaAs quantum dots, embedded in an Al0.3Ga0.7As barrier layer, were grown by a droplet epitaxy method during molecular beam epitaxy on a GaAs (001) substrate. Emission peaks of photoluminescence spectra with different excitation power, were measured as 702 nm at 0.17 mW and 690 nm at 400 mW, were blue-shifted as the excitation power increased. In addition, excitation laser power dependence of time-resolved photoluminescence of double-ring GaAs quantum dots at 10 K under 400 nm excitation wavelength was performed, revealing that photoluminescence lifetime slowly decreased in comparison to that of single disc-like quantum dots as excitation power increased, implying that carrier transfer between inner ring and outer ring could slow down the decay process. The luminescence lifetime at 10 K increased from 245 to 409 ps in the range from 0.17 to 400 mW of excitation power.
这项工作聚焦于对砷化镓量子点同心量子环复合物的动力学性质进行光谱表征。通过分子束外延在砷化镓（001）衬底上采用液滴外延法生长了嵌入Al0.3Ga0.7As势垒层中的量子环（或双环）砷化镓量子点。测量了不同激发功率下光致发光光谱的发射峰，在0.17 mW时为702 nm，在400 mW时为690 nm，随着激发功率增加发生蓝移。此外，在400 nm激发波长下对10 K时双环砷化镓量子点的时间分辨光致发光进行了激发激光功率依赖性研究，结果表明随着激发功率增加，与单盘状量子点相比，光致发光寿命缓慢下降，这意味着内圈和外圈之间的载流子转移可能会减缓衰减过程。在0.17至400 mW的激发功率范围内，10 K时的发光寿命从245 ps增加到409 ps。
