Yuan Qing, Liang Baolai, Luo Shiping, Wang Ying, Yan Qigeng, Wang Shufang, Fu Guangsheng, Mazur Yuriy I, Maidaniuk Yurii, Ware Morgan E, Salamo Gregory J
Hebei Key Laboratory of Optic-electronic Information and Materials, College of Physics Science & Technology, Hebei University, Baoding 071002, People's Republic of China.
Nanotechnology. 2020 Jul 31;31(31):315701. doi: 10.1088/1361-6528/ab8a8e. Epub 2020 Apr 17.
GaSb quantum dots (QDs) have been grown by droplet epitaxy within InAlAs barrier layers on an InP (001) substrate. The droplet growth mode facilitates a larger size (average height ∼4.5 nm) and a lower density (∼6.3 × 10 cm) for the QDs than would be expected for the 4% lattice mismatch between GaSb and InAlAs. A type-II band alignment between the GaSb QDs and the InAlAs barriers is revealed by photoluminescence (PL) through a prominent blue-shift of ∼0.11 eV resulting from a six orders of magnitude increase in excitation power. Further confirmation of the type-II nature of these QDs is found through time-resolved PL studies showing a biexponential decay with a long carrier lifetime of ∼10.9 ns. These observations reveal new information for understanding the formation and properties of GaSb/InAlAs/InP QDs, which may be an optimum system for the development of both efficient memory cells and photovoltaic devices.
通过液滴外延法在InP（001）衬底上的InAlAs势垒层内生长了GaSb量子点（QDs）。与GaSb和InAlAs之间4%的晶格失配所预期的情况相比，液滴生长模式使得量子点具有更大的尺寸（平均高度约4.5 nm）和更低的密度（约6.3×10¹⁰ cm⁻²）。通过光致发光（PL）发现，由于激发功率增加六个数量级导致约0.11 eV的显著蓝移，GaSb量子点与InAlAs势垒之间呈现II型能带排列。通过时间分辨PL研究进一步证实了这些量子点的II型性质，研究显示其具有双指数衰减，长载流子寿命约为10.9 ns。这些观察结果揭示了关于理解GaSb/InAlAs/InP量子点的形成和性质的新信息，这可能是开发高效存储单元和光伏器件的最佳系统。
