Yin Hong, Li Guodong, Jiang Chao
National Center for Nanoscience and Technology, No. 11 Beiyitiao, Zhongguancun, Beijing 100190, People's Republic of China.
J Nanosci Nanotechnol. 2013 Feb;13(2):1022-5. doi: 10.1166/jnn.2013.6105.
The excitation power dependence of radiative transitions in the type-II GaSb/GaAs quantum dots structure has been studied by the photoluminescence (PL) at different temperatures. The QDs' photoluminescence exhibits a strong blue-shift with increasing the excitation power and the peak energy (E(PL)) is proportional to the third root of excitation power. With the increase of excitation power, the nonlinear change for both the PL peak and the intensity was observed, which is attributed to the excited state transition. The thermal process and activation energy (E(a)) of electron-hole pairs at different excitation powers has also been studied for GaSb QDs. As the excitation power increases, the activation energy decreases, while E(PL) +E(a) keeps nearly constant, which is smaller than the band gap of GaAs. The decrease of E(a) is probably caused by the band bending effect.
通过在不同温度下的光致发光（PL）研究了II型GaSb/GaAs量子点结构中辐射跃迁的激发功率依赖性。量子点的光致发光随着激发功率的增加呈现出强烈的蓝移，并且峰值能量（E(PL)）与激发功率的立方根成正比。随着激发功率的增加，观察到PL峰值和强度的非线性变化，这归因于激发态跃迁。还研究了不同激发功率下GaSb量子点中电子-空穴对的热过程和激活能（E(a)）。随着激发功率的增加，激活能降低，而E(PL)+E(a)几乎保持恒定，且小于GaAs的带隙。E(a)的降低可能是由能带弯曲效应引起的。
