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Probe Type II Band Alignment in One-Dimensional Van Der Waals Heterostructures Using First-Principles Calculations
Published on: October 12, 2019
Strain-induced band gap modification in coherent core/shell nanostructures.
Shenyuan Yang1, David Prendergast, Jeffrey B Neaton
1Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA.
Nano Letters
|August 12, 2010
Summary
Strain significantly impacts the electronic band gap in core/shell semiconductor nanowires, reducing it as much as quantum confinement. This study quantifies strain effects in cadmium selenide/cadmium telluride nanostructures.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Core/shell nanowires offer tunable electronic properties.
- II-VI semiconductors like CdSe and CdTe are crucial for optoelectronics.
- Lattice mismatch in heterostructures induces strain.
Purpose of the Study:
- To investigate the interplay of quantum confinement and strain in CdSe/CdTe core/shell nanowires.
- To quantitatively separate the effects of quantum confinement and strain on electronic band gap.
- To elucidate the role of strain in nanostructure electronic and optical properties.
Main Methods:
- First-principles calculations using density functional theory (DFT).
- Simulation of core/shell nanowire geometries with varying core radii and shell thicknesses.
- Quantitative analysis to decouple strain and quantum confinement effects.
Main Results:
- Increasing CdTe shell thickness significantly reduces the CdSe core band gap.
- Strain-induced band gap reduction is comparable to quantum confinement effects.
- Anisotropic strain develops throughout the CdSe/CdTe heterostructure.
Conclusions:
- Strain plays a critical role in determining the electronic band gap of core/shell nanostructures.
- Understanding strain is essential for designing optoelectronic devices based on nanowires.
- The findings quantify the significant impact of strain in II-VI semiconductor heterostructures.
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