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Article
Improved Quantum Dot Stacking for Intermediate Band Solar Cells Using Strain Compensation
Nanotechnology
(2014)
Abstract
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.
Keywords
- strain compensation,
- tensile strain,
- self-assembled quantum dots,
- InAs/AlAsSb,
- intermediate band solar cells
Disciplines
Publication Date
November 7, 2014
Citation Information
Paul J. Simmonds, Meng Sun, Ramesh Babu Laghumavarapu, Baolai Liang, et al.. "Improved Quantum Dot Stacking for Intermediate Band Solar Cells Using Strain Compensation" Nanotechnology Vol. 25 Iss. 44 (2014) Available at: http://works.bepress.com/paul_simmonds/62/