scholarly journals 3D continuum phonon model for group-IV 2D materials

2017 ◽  
Vol 8 ◽  
pp. 1345-1356 ◽  
Author(s):  
Morten Willatzen ◽  
Lok C Lew Yan Voon ◽  
Appala Naidu Gandi ◽  
Udo Schwingenschlögl
Keyword(s):  
Molybdenum Disulfide ◽  
Density Functional ◽  
Three Dimensional ◽  
Functional Results ◽  
Group Iv ◽  
Two Dimensional ◽  
Phonon Modes ◽  
Long Wavelength ◽  
Phonon Spectra ◽  
Two Dimensional Materials

A general three-dimensional continuum model of phonons in two-dimensional materials is developed. Our first-principles derivation includes full consideration of the lattice anisotropy and flexural modes perpendicular to the layers and can thus be applied to any two-dimensional material. In this paper, we use the model to not only compare the phonon spectra among the group-IV materials but also to study whether these phonons differ from those of a compound material such as molybdenum disulfide. The origin of quadratic modes is clarified. Mode coupling for both graphene and silicene is obtained, contrary to previous works. Our model allows us to predict the existence of confined optical phonon modes for the group-IV materials but not for molybdenum disulfide. A comparison of the long-wavelength modes to density-functional results is included.

scholarly journals Polarization-sensitive photodetectors based on three-dimensional molybdenum disulfide (MoS2) field-effect transistors

Nanophotonics ◽  
2020 ◽  
Vol 9 (16) ◽  
pp. 4719-4728
Author(s):  
Tao Deng ◽  
Shasha Li ◽  
Yuning Li ◽  
Yang Zhang ◽  
Jingye Sun ◽  
...  
Keyword(s):  
Molybdenum Disulfide ◽  
Field Effect ◽  
High Performance ◽  
Field Effect Transistors ◽  
Three Dimensional ◽  
Polarized Light ◽  
Optical Field ◽  
Two Dimensional ◽  
Polarization Ratio ◽  
Two Dimensional Materials

AbstractThe molybdenum disulfide (MoS2)-based photodetectors are facing two challenges: the insensitivity to polarized light and the low photoresponsivity. Herein, three-dimensional (3D) field-effect transistors (FETs) based on monolayer MoS2 were fabricated by applying a self–rolled-up technique. The unique microtubular structure makes 3D MoS2 FETs become polarization sensitive. Moreover, the microtubular structure not only offers a natural resonant microcavity to enhance the optical field inside but also increases the light-MoS2 interaction area, resulting in a higher photoresponsivity. Photoresponsivities as high as 23.8 and 2.9 A/W at 395 and 660 nm, respectively, and a comparable polarization ratio of 1.64 were obtained. The fabrication technique of the 3D MoS2 FET could be transferred to other two-dimensional materials, which is very promising for high-performance polarization-sensitive optical and optoelectronic applications.

scholarly journals Anomalous strain effect on the thermal conductivity of low-buckled two-dimensional silicene

2020 ◽  
Author(s):  
Bin Ding ◽  
Xiaoyan Li ◽  
Wuxing Zhou ◽  
Gang Zhang ◽  
Huajian Gao
Keyword(s):  
Thermal Conductivity ◽  
Strain Effect ◽  
Two Dimensional ◽  
Phonon Modes ◽  
Heat Management ◽  
Anomalous Effect ◽  
Long Wavelength ◽  
Two Dimensional Materials ◽  
Dynamics Simulations ◽  
Energy Conversion Devices

Abstract The thermal conductivity of two-dimensional materials, such as graphene, typically decreases when tensile strain is applied, which softens their phonon modes. Here, we report an anomalous strain effect on the thermal conductivity of monolayer silicene, a representative low-buckled two-dimensional (LB-2D) material. ReaxFF-based molecular dynamics simulations are performed to show that biaxially stretched monolayer silicene exhibits a remarkable increase in the thermal conductivity, by as much as 10 times the freestanding value, with increasing applied strain in the range of [0, 0.1], which is attributed to increased contributions from long-wavelength phonons. A further increase in strain in the range of [0.11, 0.18] results in a plateau of the thermal conductivity in an oscillatory manner, governed by a unique dynamic bonding behavior under extreme loading. This anomalous effect reveals new physical insights into the thermal properties of LB-2D materials and may provide some guidelines for designing heat management and energy conversion devices based on such materials.

Interfacial properties of borophene contacts with two-dimensional semiconductors

2017 ◽  
Vol 19 (35) ◽  
pp. 23982-23989 ◽  
Author(s):  
Jie Yang ◽  
Ruge Quhe ◽  
Shenyan Feng ◽  
Qiaoxuan Zhang ◽  
Ming Lei ◽  
...  
Keyword(s):  
Density Functional ◽  
Transition Metal Dichalcogenides ◽  
Dft Method ◽  
Interfacial Properties ◽  
Group Iv ◽  
Two Dimensional ◽  
Functional Theory ◽  
Group V ◽  
Two Dimensional Materials ◽  
Metal Dichalcogenides

Interfacial properties of β12phase borophene contacts with other common two-dimensional materials (transition-metal dichalcogenides, group IV-enes and group V-enes) have been systematically studied using a density functional theory (DFT) method.

Large-scale fabrication of a flexible, highly conductive composite paper based on molybdenum disulfide–Pt nanoparticle–single-walled carbon nanotubes for efficient hydrogen production

2017 ◽  
Vol 53 (2) ◽  
pp. 380-383 ◽  
Author(s):  
I-Wen Peter Chen ◽  
Yu-Xiang Chen ◽  
Chien-Wei Wu ◽  
Chun-Chien Chiu ◽  
Yu-Chieh Hsieh
Keyword(s):  
Carbon Nanotubes ◽  
Hydrogen Production ◽  
Molybdenum Disulfide ◽  
Large Scale ◽  
Single Walled Carbon Nanotubes ◽  
Two Dimensional ◽  
Pt Nanoparticle ◽  
Two Dimensional Materials ◽  
Walled Carbon Nanotubes ◽  
Composite Paper

Creating efficient hydrogen production properties from the macroscopic assembly of two-dimensional materials is still an unaccomplished goal.

High-yield fabrication of suspended two-dimensional materials for atomic resolution imaging

RSC Advances ◽  
2016 ◽  
Vol 6 (80) ◽  
pp. 76273-76279 ◽  
Author(s):  
Jaehyun Han ◽  
Jun-Young Lee ◽  
Jeongun Choe ◽  
Jong-Souk Yeo
Keyword(s):  
Three Dimensional ◽  
Atomic Resolution ◽  
High Yield ◽  
Two Dimensional ◽  
Two Dimensional Materials ◽  
Resolution Imaging

Two-dimensional (2D) atomic crystals are very interesting materials due to their unique properties, which are significantly different than those observed in conventional three-dimensional (3D) materials.

scholarly journals Tip-Based Nanomachining on Thin Films: A Mini Review

2021 ◽  
Author(s):  
Shunyu Chang ◽  
Yanquan Geng ◽  
Yongda Yan
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Data Storage ◽  
Three Dimensional ◽  
Maintenance Cost ◽  
Two Dimensional ◽  
Force Microscopy ◽  
Atomic Force ◽  
Current State ◽  
Two Dimensional Materials

AbstractAs one of the most widely used nanofabrication methods, the atomic force microscopy (AFM) tip-based nanomachining technique offers important advantages, including nanoscale manipulation accuracy, low maintenance cost, and flexible experimental operation. This technique has been applied to one-, two-, and even three-dimensional nanomachining patterns on thin films made of polymers, metals, and two-dimensional materials. These structures are widely used in the fields of nanooptics, nanoelectronics, data storage, super lubrication, and so forth. Moreover, they are believed to have a wide application in other fields, and their possible industrialization may be realized in the future. In this work, the current state of the research into the use of the AFM tip-based nanomachining method in thin-film machining is presented. First, the state of the structures machined on thin films is reviewed according to the type of thin-film materials (i.e., polymers, metals, and two-dimensional materials). Second, the related applications of tip-based nanomachining to film machining are presented. Finally, the current situation of this area and its potential development direction are discussed. This review is expected to enrich the understanding of the research status of the use of the tip-based nanomachining method in thin-film machining and ultimately broaden its application.

scholarly journals Mechanochemical Synthesis of a Mercury(II) Metal-Organic Framework Reveals a Two-Dimensional Polymorph Stabilized by Weak Interactions

2019 ◽  
Author(s):  
Isaiah R. Speight ◽  
Igor Huskić ◽  
Mihails Arhangelskis ◽  
Hatem M. Titi ◽  
Robin Stein ◽  
...  
Keyword(s):  
Density Functional ◽  
Weak Interactions ◽  
Metal Organic Framework ◽  
Three Dimensional ◽  
Density Functional Theory Calculations ◽  
Dimensional Structure ◽  
Reaction Monitoring ◽  
Two Dimensional ◽  
Functional Theory ◽  
Metal Organic

Solid-state mechanochemistry revealed a novel polymorph of the mercury(II) imidazolate framework, based on square-grid (sql) topology layers. Reaction monitoring and periodic density functional theory calculations show that the sql-structure is of higher stability than the previously reported three-dimensional structure, with the unexpected stabilization of a lower dimensionality structure explained by contributions of weak interactions, which include short C-H···Hg contacts.

Elemental Group IV Two-Dimensional Materials Beyond Graphene

2016 ◽  
pp. 149-188 ◽  
Author(s):  
M.E. Dávila ◽  
L.C. Lew Yan Voon ◽  
J. Zhao ◽  
G. Le Lay
Keyword(s):  
Group Iv ◽  
Two Dimensional ◽  
Two Dimensional Materials
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