Simmonds Paul J, Sun Meng, Laghumavarapu Ramesh Babu, Liang Baolai, Norman Andrew G, Luo Jun-Wei, Huffaker Diana L
California NanoSystems Institute, UCLA, Los Angeles, CA 90095, USA.
Nanotechnology. 2014 Nov 7;25(44):445402. doi: 10.1088/0957-4484/25/44/445402. Epub 2014 Oct 16.
We use thin tensile-strained AlAs layers to manage compressive strain in stacked layers of InAs/AlAsSb quantum dots (QDs). The AlAs layers allow us to reduce residual strain in the QD stacks, suppressing strain-related defects. AlAs layers 2.4 monolayers thick are sufficient to balance the strain in the structures studied, in agreement with theory. Strain balancing improves material quality and helps increase QD uniformity by preventing strain accumulation and ensuring that each layer of InAs experiences the same strain. Stacks of 30 layers of strain-balanced QDs exhibit carrier lifetimes as long as 9.7 ns. QD uniformity is further enhanced by vertical ABAB… ordering of the dots in successive layers. Strain compensated InAs/AlAsSb QD stacks show great promise for intermediate band solar cell applications.
我们使用薄的拉伸应变AlAs层来管理InAs/AlAsSb量子点（QD）堆叠层中的压应变。AlAs层使我们能够降低量子点堆叠中的残余应变，抑制与应变相关的缺陷。2.4个单层厚的AlAs层足以平衡所研究结构中的应变，这与理论相符。应变平衡提高了材料质量，并通过防止应变积累和确保每层InAs经历相同的应变来帮助提高量子点的均匀性。30层应变平衡量子点的堆叠显示出长达9.7 ns的载流子寿命。通过连续层中量子点的垂直ABAB…排列，量子点的均匀性进一步提高。应变补偿的InAs/AlAsSb量子点堆叠在中间带太阳能电池应用中显示出巨大的潜力。
