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Nanomaterials 2018, 8(9), 709; https://doi.org/10.3390/nano8090709

A High-Throughput Study of the Electronic Structure and Physical Properties of Short-Period (GaAs)m(AlAs)n (m, n ≤ 10) Superlattices Based on Density Functional Theory Calculations

1
Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China
2
Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
*
Author to whom correspondence should be addressed.
Received: 13 August 2018 / Revised: 5 September 2018 / Accepted: 6 September 2018 / Published: 10 September 2018
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Abstract

As important functional materials, the electronic structure and physical properties of (GaAs)m(AlAs)n superlattices (SLs) have been extensively studied. However, due to limitations of computational methods and computational resources, it is sometimes difficult to thoroughly understand how and why the modification of their structural parameters affects their electronic structure and physical properties. In this article, a high-throughput study based on density functional theory calculations has been carried out to obtain detailed information and to further provide the underlying intrinsic mechanisms. The band gap variations of (GaAs)m(AlAs)n superlattices have been systematically investigated and summarized. They are very consistent with the available reported experimental measurements. Furthermore, the direct-to-indirect-gap transition of (GaAs)m(AlAs)n superlattices has been predicted and explained. For certain thicknesses of the GaAs well (m), the band gap value of (GaAs)m(AlAs)n SLs exponentially increases (increasing n), while for certain thicknesses of the AlAs barrier (n), the band gap value of (GaAs)m(AlAs)n SLs exponentially decreases (increasing m). In both cases, the band gap values converge to certain values. Furthermore, owing to the energy eigenvalues at different k-points showing different variation trends, (GaAs)m(AlAs)n SLs transform from a Γ-Γ direct band gap to Γ-M indirect band gap when the AlAs barrier is thick enough. The intrinsic reason for these variations is that the contributions and positions of the electronic states of the GaAs well and the AlAs barrier change under altered thickness conditions. Moreover, we have found that the binding energy can be used as a detector to estimate the band gap value in the design of (GaAs)m(AlAs)n devices. Our findings are useful for the design of novel (GaAs)m(AlAs)n superlattices-based optoelectronic devices. View Full-Text
Keywords: superlattices; high-throughput study; density functional theory calculations; electronic structure superlattices; high-throughput study; density functional theory calculations; electronic structure
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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).
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Liu, Q.-L.; Zhao, Z.-Y.; Yi, J.-H.; Zhang, Z.-Y. A High-Throughput Study of the Electronic Structure and Physical Properties of Short-Period (GaAs)m(AlAs)n (m, n ≤ 10) Superlattices Based on Density Functional Theory Calculations. Nanomaterials 2018, 8, 709.

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