Electronic and Mechanical Coupling in Elastically Bent ZnO Micro/Nanowires

ABSTRACTElastic engineering strain has been regarded as a low-cost and continuously variable manner for altering the physical and chemical properties of materials, and it becomes even more important at low-dimensionality because at micro/nanoscale, materials/structures can usually bear exceptionally high elastic strains before failure. The elastic strain effects are therefore greatly magnified in micro/nanoscale structures and should be of great potential in the design of novel functional devices. The purpose of this overview is to present a summary of our recently progress in the energy band engineering of elastically bent ZnO micro/nanowires. First, we present the electronic and mechanical coupling effect in bent ZnO nanowires. Second, we summary the bending strain gradient effect on the near-band-edge (NBE) emission photon energy of bent ZnO micro/nanowires. Third, we show that the strain can induce exciton fine-structure splitting and shift in ZnO microwires. Our recent progresses illustrate that the electronic band structure of ZnO micro/nanowires can be dramatically tuned by elastic strain engineering, and point to potential future applications based on the elastic strain engineering of ZnO micro/nanowires.

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Machine learning for deep elastic strain engineering of semiconductor electronic band structure and effective mass

npj Computational Materials ◽

10.1038/s41524-021-00538-0 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Evgenii Tsymbalov ◽

Zhe Shi ◽

Ming Dao ◽

Subra Suresh ◽

Ju Li ◽

...

Keyword(s):

Machine Learning ◽

Deep Learning ◽

Band Structure ◽

Physical Properties ◽

Elastic Strain ◽

Electronic Band Structure ◽

Strain Engineering ◽

Semiconductor Materials ◽

Electronic Band ◽

Effective Electron

AbstractThe controlled introduction of elastic strains is an appealing strategy for modulating the physical properties of semiconductor materials. With the recent discovery of large elastic deformation in nanoscale specimens as diverse as silicon and diamond, employing this strategy to improve device performance necessitates first-principles computations of the fundamental electronic band structure and target figures-of-merit, through the design of an optimal straining pathway. Such simulations, however, call for approaches that combine deep learning algorithms and physics of deformation with band structure calculations to custom-design electronic and optical properties. Motivated by this challenge, we present here details of a machine learning framework involving convolutional neural networks to represent the topology and curvature of band structures in k-space. These calculations enable us to identify ways in which the physical properties can be altered through “deep” elastic strain engineering up to a large fraction of the ideal strain. Algorithms capable of active learning and informed by the underlying physics were presented here for predicting the bandgap and the band structure. By training a surrogate model with ab initio computational data, our method can identify the most efficient strain energy pathway to realize physical property changes. The power of this method is further demonstrated with results from the prediction of strain states that influence the effective electron mass. We illustrate the applications of the method with specific results for diamonds, although the general deep learning technique presented here is potentially useful for optimizing the physical properties of a wide variety of semiconductor materials.

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A First-Principles Study of Nonlinear Elastic Behavior and Anisotropic Electronic Properties of Two-Dimensional HfS2

Nanomaterials ◽

10.3390/nano10030446 ◽

2020 ◽

Vol 10 (3) ◽

pp. 446

Author(s):

Mahdi Faghihnasiri ◽

Aidin Ahmadi ◽

Samaneh Alvankar Golpayegan ◽

Saeideh Garosi Sharifabadi ◽

Ali Ramazani

Keyword(s):

Electronic Properties ◽

First Principles ◽

Electronic Band Structure ◽

Hexagonal Phase ◽

Strain Engineering ◽

Elastic Behavior ◽

Potential Candidate ◽

Two Dimensional ◽

Electronic Band ◽

Wide Range

We utilize first principles calculations to investigate the mechanical properties and strain-dependent electronic band structure of the hexagonal phase of two dimensional (2D) HfS2. We apply three different deformation modes within −10% to 30% range of two uniaxial (D1, D2) and one biaxial (D3) strains along x, y, and x-y directions, respectively. The harmonic regions are identified in each deformation mode. The ultimate stress for D1, D2, and D3 deformations is obtained as 0.037, 0.038 and 0.044 (eV/Ang3), respectively. Additionally, the ultimate strain for D1, D2, and D3 deformation is obtained as 17.2, 17.51, and 21.17 (eV/Ang3), respectively. In the next step, we determine the second-, third-, and fourth-order elastic constants and the electronic properties of both unstrained and strained HfS2 monolayers are investigated. Our findings reveal that the unstrained HfS2 monolayer is a semiconductor with an indirect bandgap of 1.12 eV. We then tune the bandgap of HfS2 with strain engineering. Our findings reveal how to tune and control the electronic properties of HfS2 monolayer with strain engineering, and make it a potential candidate for a wide range of applications including photovoltaics, electronics and optoelectronics.

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Strain regulated interlayer coupling in WSe2/WS2 heterobilayer

Nanotechnology ◽

10.1088/1361-6528/ac3a39 ◽

2021 ◽

Author(s):

Xiaodan Xu ◽

Cong Wang ◽

Wenqi Xiong ◽

Yang Liu ◽

Donghao Yang ◽

...

Keyword(s):

Tensile Strain ◽

Electronic Band Structure ◽

2D Materials ◽

Interlayer Coupling ◽

Strain Engineering ◽

Atomic Scale ◽

Nanometer Scale ◽

Photoluminescence Intensity ◽

Practical Application ◽

Electronic Band

Abstract Strain engineering can effectively modify the materials lattice parameters at atomic scale, hence it has become an efficient method for tuning the physical properties of two-dimensional (2D) materials. The study of the strain regulated interlayer coupling is deserved for different kinds of heterostructures. Here, we systematically studied the strain engineering of WSe2/WS2 heterostructures as well as their constituent monolayers. The measured Raman and photoluminescence spectra demonstrate that the strain can evidently modulate the phonon energy and exciton emission of monolayer WSe2 and WS2 as well as the WSe2/WS2 heterostructures. The tensile strain can tune the electronic band structure of WSe2/WS2 heterostructure, as well as enhance the interlayer coupling. It is further revealed that the photoluminescence intensity ratio of WS2 to WSe2 in our WSe2/WS2 heterobilayer increases monotonically with tensile strain. These findings can broaden the understanding and practical application of strain engineering in 2D materials with nanometer-scale resolution.

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Soft-chemistry Route to P-I-N Heterostructured Quantum Dot Electroluminescence Device: All Solution-processed Polymer-Inorganic Hybrid QD-EL Device

MRS Proceedings ◽

10.1557/proc-0959-m04-05 ◽

2006 ◽

Vol 959 ◽

Author(s):

Soon-Jae Kwon ◽

Kyung-Sang Cho ◽

Byoung-Lyong Choi ◽

Byung-Ki Kim

Keyword(s):

Quantum Dot ◽

Electronic Band Structure ◽

Low Cost ◽

Sol Gel ◽

Device Structure ◽

Electronic Band ◽

Solution Processed ◽

Turn On ◽

Ito Glass ◽

Polymer Semiconductor

ABSTRACTp-i-n heterostructured quantum-dot electroluminescence (QD-EL) device was fabricated by soft-chemical process, which shows a low turn-on voltage comparable to OLEDs. To construct the multilayered device structure, p-type polymer semiconductor was deposited on the ITO glass by sequential process of coating and thermal curing, thereupon a few monolayers of QD was spin-coated. n-type metal-oxide film was deposited on top of the QD luminescence layer by sol-gel method, providing a facile and low-cost route for the ETL fabrication. Prior to solution-processed ETL construction, a post-treatment is performed using cross-linking agent, in order to chemically-immobilize the QDs. As a cathodic electrode, relatively air-stable aluminum was deposited. The constituent material as well as the electronic band structure of the integrated device guarantees operating stability in air and low turn-on voltage.

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First-Principles Study of Energy Band Gap of Graphene-Like B-C-N by Strain

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.476-478.1313 ◽

2012 ◽

Vol 476-478 ◽

pp. 1313-1317 ◽

Cited By ~ 1

Author(s):

Xin Miao Xu ◽

Yu Lu

Keyword(s):

Band Gap ◽

First Principles ◽

Energy Band ◽

Tensile Deformation ◽

Electronic Band Structure ◽

Strain Engineering ◽

Monolayer Graphene ◽

Energy Band Gap ◽

Electronic Band ◽

Hexagonal Sheet

We report a first-principles investigation on BN dopped monolayer graphene sheet and examined the electronic band structure and band gaps in equilibrium state and under strain. The obtained results reveal that the doping of B-N pairs on the hexagonal sheet can open the gap at the Dirac-like point. With heavy doping and more B-N bonds the energy bad gap is found to be larger. Upon tensile deformation, the dopped BCN monolayer sheet represents a strong anisotropic stress-strain relation. Detailed strain-gap relation investigation reveals that the energy band gap presents desperate variation trends for strain applied along and direction. Versatile band-gap modulation schemes can then be obtained through direction-dependent strain engineering of the BCN nanosheet..

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Progress in Photocatalysis of g-C3N4 and its Modified Compounds

E3S Web of Conferences ◽

10.1051/e3sconf/202123301114 ◽

2021 ◽

Vol 233 ◽

pp. 01114

Author(s):

Yanling Wu ◽

Yanmin Wang ◽

Miantuo Li

Keyword(s):

Environmental Remediation ◽

Carbon Nitride ◽

Electronic Band Structure ◽

Low Cost ◽

Sustainable Utilization ◽

Electronic Band ◽

Semiconductor Electronic ◽

Visible Light Active ◽

Metallic Catalyst ◽

Splitting Water

Recently, graphitic carbon nitride (g-C3N4), a polymeric semiconductorhas been widely used as a low-cost, stable, and metal-free visible-light-active photocatalyst in the sustainable utilization of solar energy, such as water splitting, organic photosynthesis, and environmental remediation, which has attracted world wide attention from energy and environmental relative fields. Base on analysis of structure and theoretical calculation, the reasons that g-C3N4 can be used as a non-metallic catalyst were discussed in this paper. Some group's research jobs that metal-supported g-C3N4, metal-supported g-C3N4/organnic semiconductor compound and heterogeneous junction adjust the semiconductor electronic band structure have been summarized. And the mechanism, effect factors, and research developments on the reaction of organic degradation by photocatalytic and splitting water for hydrogen revolution catalyzed by above-mentioned modified g-C3N4 were emphatically analyzed. Finally, the prospects for the development of highly efficient g-C3N4 based photocatalysts are also discussed.

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Strain Engineering of Electronic Band Structure and Optical Absorption Spectra of Helically Coiled Carbon Nanotubes

Journal of Nanoelectronics and Optoelectronics ◽

10.1166/jno.2013.1456 ◽

2013 ◽

Vol 8 (2) ◽

pp. 160-164 ◽

Cited By ~ 2

Author(s):

S. Dmitrović ◽

Z. P. Popović ◽

M. Damnjanović ◽

I. Milošević

Keyword(s):

Carbon Nanotubes ◽

Optical Absorption ◽

Band Structure ◽

Absorption Spectra ◽

Electronic Band Structure ◽

Strain Engineering ◽

Optical Absorption Spectra ◽

Electronic Band

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PROPERTIES OF ZnO NANOWIRES AND FUNCTIONAL NANOCOMPOSITES

International Journal of Nanoscience ◽

10.1142/s0219581x08005134 ◽

2008 ◽

Vol 07 (01) ◽

pp. 29-35 ◽

Cited By ~ 1

Author(s):

RYSZARD PYRZ

Keyword(s):

Cross Section ◽

Electronic Band Structure ◽

Zno Nanowires ◽

Sensors And Actuators ◽

Electronic Band ◽

One Dimensional ◽

Mechanical Coupling ◽

Deformation State ◽

Dynamics Simulations ◽

Controllable Size

One-dimensional structures like nanotubes and nanowires are potential candidates for nanoscale sensors and actuators. Furthermore, the nanoscale cross-section of these elements introduces controllable size effects while the macroscopic length ensures good mechanical coupling to matrix materials and thus reinforcing effects in nanocomposites. Molecular dynamics simulations are employed to study the electronic and mechanical properties of smallest ZnO nanowires. It has been shown that the electronic band structure of nanowires varies with uniaxial strain and this property can be used for sensing deformation state when nanowires are embedded in a polymer matrix.

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