scholarly journals Computational exploration of two-dimensional silicon diarsenide and germanium arsenide for photovoltaic applications

2018 ◽  
Vol 9 ◽  
pp. 1247-1253 ◽  
Author(s):  
Sri Kasi Matta ◽  
Chunmei Zhang ◽  
Yalong Jiao ◽  
Anthony O'Mullane ◽  
Aijun Du
Keyword(s):  
Density Functional ◽  
2D Materials ◽  
Single Layer ◽  
Group Iv ◽  
Two Dimensional ◽  
Hybrid Functional ◽  
New Family ◽  
Photovoltaic Applications ◽  
Computational Exploration ◽  
Mechanical Cleavage

The properties of bulk compounds required to be suitable for photovoltaic applications, such as excellent visible light absorption, favorable exciton formation, and charge separation are equally essential for two-dimensional (2D) materials. Here, we systematically study 2D group IV–V compounds such as SiAs2 and GeAs2 with regard to their structural, electronic and optical properties using density functional theory (DFT), hybrid functional and Bethe–Salpeter equation (BSE) approaches. We find that the exfoliation of single-layer SiAs2 and GeAs2 is highly feasible and in principle could be carried out experimentally by mechanical cleavage due to the dynamic stability of the compounds, which is inferred by analyzing their vibrational normal mode. SiAs2 and GeAs2 monolayers possess a bandgap of 1.91 and 1.64 eV, respectively, which is excellent for sunlight harvesting, while the exciton binding energy is found to be 0.25 and 0.14 eV, respectively. Furthermore, band-gap tuning is also possible by application of tensile strain. Our results highlight a new family of 2D materials with great potential for solar cell applications.

Theoretical investigation on the photocatalytic activity of the Au/g-C3N4 monolayer

2017 ◽  
Vol 16 (02) ◽  
pp. 1750013 ◽  
Author(s):  
Guoyan Nie ◽  
Peng Li ◽  
Jin-Xia Liang ◽  
Chun Zhu
Keyword(s):  
Optical Properties ◽  
Photocatalytic Activity ◽  
Density Functional ◽  
High Stability ◽  
Carbon Nitride ◽  
Visible Region ◽  
Single Layer ◽  
Single Atom ◽  
Two Dimensional ◽  
Hybrid Functional

Two-dimensional optical catalysis materials have a wonderful potential application. Here, a new two-dimensional material consisting of the supported single-atom Au on a graphite carbon nitride (g-C3N[Formula: see text] single layer has been designed and its electronic and optical properties have been characterized by density functional calculations. The bandgap of 1.82[Formula: see text]eV calculated by the hybrid functional HSE06 shows that the Au/g-C3N4 is an indirect semiconductor, and the electron can easily be excited from the single-atom Au to the bottom of the conduction band. This material therefore has relatively strong optical properties in the visible region. Moreover, the process of Au insertion into the cavity of g-C3N4 single layer is energy-favorable. This work may provide insights and a new avenue for fabricating supported Au catalysts with high stability.

Co-planar two-dimensional Metal-Insulator-Semiconductor Capacitor: Numerical study of the device electrostatics.

2017 ◽  
Author(s):  
Varun Bheemireddy
Keyword(s):  
Space Charge ◽  
High Performance ◽  
Numerical Study ◽  
2D Materials ◽  
Space Charge Density ◽  
Two Dimensional ◽  
Short Channel ◽  
Metal Insulator ◽  
Metal Insulator Semiconductor ◽  
New Family

The two-dimensional(2D) materials are highly promising candidates to realise elegant and e cient transistor. In the present letter, we conjecture a novel co-planar metal-insulator-semiconductor(MIS) device(capacitor) completely based on lateral 2D materials architecture and perform numerical study of the capacitor with a particular emphasis on its di erences with the conventional 3D MIS electrostatics. The space-charge density features a long charge-tail extending into the bulk of the semiconductor as opposed to the rapid decay in 3D capacitor. Equivalently, total space-charge and semiconductor capacitance densities are atleast an order of magnitude more in 2D semiconductor. In contrast to the bulk capacitor, expansion of maximum depletion width in 2D semiconductor is observed with increasing doping concentration due to lower electrostatic screening. The heuristic approach of performance analysis(2D vs 3D) for digital-logic transistor suggest higher ON-OFF current ratio in the long-channel limit even without third dimension and considerable room to maximise the performance of short-channel transistor. The present results could potentially trigger the exploration of new family of co-planar at transistors that could play a signi significant role in the future low-power and/or high performance electronics.<br>

scholarly journals Stone–Wales defects preserve hyperuniformity in amorphous two-dimensional networks

2021 ◽  
Vol 118 (3) ◽  
pp. e2016862118
Author(s):  
Duyu Chen ◽  
Yu Zheng ◽  
Lei Liu ◽  
Ge Zhang ◽  
Mohan Chen ◽  
...  
Keyword(s):  
2D Materials ◽  
Single Layer ◽  
Salient Feature ◽  
Density Fluctuations ◽  
Wave Number ◽  
Static Structure Factor ◽  
Two Dimensional ◽  
Static Structure ◽  
Topological Transformation ◽  
Amorphous Graphene

Disordered hyperuniformity (DHU) is a recently discovered novel state of many-body systems that possesses vanishing normalized infinite-wavelength density fluctuations similar to a perfect crystal and an amorphous structure like a liquid or glass. Here, we discover a hyperuniformity-preserving topological transformation in two-dimensional (2D) network structures that involves continuous introduction of Stone–Wales (SW) defects. Specifically, the static structure factor S(k) of the resulting defected networks possesses the scaling S(k)∼kα for small wave number k, where 1≤α(p)≤2 monotonically decreases as the SW defect concentration p increases, reaches α≈1 at p≈0.12, and remains almost flat beyond this p. Our findings have important implications for amorphous 2D materials since the SW defects are well known to capture the salient feature of disorder in these materials. Verified by recently synthesized single-layer amorphous graphene, our network models reveal unique electronic transport mechanisms and mechanical behaviors associated with distinct classes of disorder in 2D materials.

Half-metallic ferromagnetism prediction in MoS2-based two-dimensional superlattice from first-principles

2018 ◽  
Vol 32 (07) ◽  
pp. 1850098 ◽  
Author(s):  
Yan-Ni Wen ◽  
Peng-Fei Gao ◽  
Ming-Gang Xia ◽  
Sheng-Li Zhang
Keyword(s):  
Structural Stability ◽  
Density Functional ◽  
2D Materials ◽  
Two Dimensional ◽  
Spin Filter ◽  
Half Metallic ◽  
Hexagonal Ring ◽  
Electrical And Magnetic Properties ◽  
Metallic Ferromagnetism ◽  
Half Metallic Ferromagnetism

Half-metallic ferromagnetism (HMFM) has great potential application in spin filter. However, it is extremely rare, especially in two-dimensional (2D) materials. At present, 2D materials have drawn international interest in spintronic devices. Here, we use ab initio density functional theory (DFT) calculations to study the structural stability and electrical and magnetic properties of the MoS2-based 2D superlattice formed by inserting graphene hexagonal ring in [Formula: see text] MoS2 supercell. Two kinds of structures with hexagonal carbon ring were predicted with structural stability and were shown HMFM. The two structures combine the spin transport capacity of graphene with the magnetism of the defective 2D MoS2. And they have strong covalent bonding between the C and S or Mo atoms near the interface. This work is very useful to help us to design reasonable MoS2-based spin filter.

Two-dimensional metal-organic frameworks Mo3(C2O)12 as promising single-atom catalysts for selective nitrogen-to-ammonia

2022 ◽  
Author(s):  
Zhen Feng ◽  
Zelin Yang ◽  
Xiaowen Meng ◽  
Fachuang Li ◽  
Zhanyong Guo ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Metal Organic Frameworks ◽  
Density Functional Theory Calculations ◽  
Reduction Reaction ◽  
Single Atom ◽  
Two Dimensional ◽  
Functional Theory ◽  
New Family ◽  
Metal Organic

The development of single-atom catalysts (SACs) for electrocatalytic nitrogen reduction reaction (NRR) remains a great challenge. Using density functional theory calculations, we design a new family of two-dimensional metal-organic frameworks...

scholarly journals Cross-plane transport in a single-molecule two-dimensional van der Waals heterojunction

2020 ◽  
Vol 6 (22) ◽  
pp. eaba6714 ◽  
Author(s):  
Shiqiang Zhao ◽  
Qingqing Wu ◽  
Jiuchan Pi ◽  
Junyang Liu ◽  
Jueting Zheng ◽  
...  
Keyword(s):  
Charge Transport ◽  
Single Molecule ◽  
Density Functional ◽  
Electronic Materials ◽  
2D Materials ◽  
Molecular Layer ◽  
Van Der Waals ◽  
Density Functional Theory Calculations ◽  
Two Dimensional ◽  
Guest Molecules

Two-dimensional van der Waals heterojunctions (2D-vdWHs) stacked from atomically thick 2D materials are predicted to be a diverse class of electronic materials with unique electronic properties. These properties can be further tuned by sandwiching monolayers of planar organic molecules between 2D materials to form molecular 2D-vdWHs (M-2D-vdWHs), in which electricity flows in a cross-plane way from one 2D layer to the other via a single molecular layer. Using a newly developed cross-plane break junction technique, combined with density functional theory calculations, we show that M-2D-vdWHs can be created and that cross-plane charge transport can be tuned by incorporating guest molecules. The M-2D-vdWHs exhibit distinct cross-plane charge transport signatures, which differ from those of molecules undergoing in-plane charge transport.

Hydrogenation as a source of superconductivity in two-dimensional TiB2

2021 ◽  
pp. 2150057
Author(s):  
Hui Wang ◽  
Chen Pan ◽  
Sheng-Yan Wang ◽  
Hong Jiang ◽  
Yin-Chang Zhao ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Vibration Frequency ◽  
First Principles ◽  
Density Functional ◽  
Tensile Strain ◽  
2D Materials ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Density Functional Perturbation Theory ◽  
Potential Applications

Using first-principles calculations based on density functional perturbation theory, we demonstrate hydrogenation-induced superconductivity in monolayer TiB2H. Hydrogen adatoms destroy the Dirac state of monolayer TiB2 and monolayer TiB2H has a high vibration frequency. Monolayer TiB2H is a phonon-mediated superconductor. Monolayer TiB2H has a predicted [Formula: see text] of 8[Formula: see text]K, which further increases under external tensile strain. Thus, this study extends our understanding of superconductivity in two-dimensional (2D) materials and its potential applications.

scholarly journals Liquid-Phase Exfoliation of Poly(Dicarbon Monofluoride) (C2F)n

2020 ◽  
Author(s):  
Xianjue Chen ◽  
Marc Dubois ◽  
Silvana Radescu Cioranescu ◽  
Aditya Rawal ◽  
Chuan Zhao
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Single Layer ◽  
Two Dimensional ◽  
Functional Theory ◽  
Carbon Allotrope ◽  
Spectroscopic Analyses ◽  
The Density Functional Theory ◽  
New Form ◽  
Liquid Phase Exfoliation

Fluorinated single-layer diamond (“F-diamond”) is a new form of two-dimensional carbon allotrope. Herein, poly(dicarbon monofluoride) (C<sub>2</sub>F)<sub>n</sub> that is essentially made of stacked layers of “F-diamane” has been synthesized and exfoliated in a variety of solvents to yield well-dispersed ultrathin sheets. Microscopic and spectroscopic analyses revealed that the exfoliated sheets retained the “F-diamane”-like structure. The experimental results are supported by the density functional theory (DFT) calculations.

scholarly journals Two-Dimensional SiP, SiAs, GeP and GeAs as Promising Candidates for Photocatalytic Applications

Coatings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 522 ◽  
Author(s):  
Bohayra Mortazavi ◽  
Masoud Shahrokhi ◽  
Gianaurelio Cuniberti ◽  
Xiaoying Zhuang
Keyword(s):  
Water Splitting ◽  
Density Functional ◽  
Visible Spectrum ◽  
Group Iv ◽  
Conduction Band Edge ◽  
Two Dimensional ◽  
Critical Feature ◽  
Functional Theory ◽  
Solar Water ◽  
Solar Water Splitting

Group IV–V-type layered materials, such as SiP, SiAs, GeP and GeAs, are among the most attractive two-dimensional (2D) materials that exhibit anisotropic mechanical, optical and transport properties. In this short communication, we conducted density functional theory simulations to explore the prospect of SiP, SiAs, GeP and GeAs nanosheets for the water-splitting application. The semiconducting gaps of stress-free SiP, SiAs, GeP and GeAs monolayers were estimated to be 2.59, 2.34, 2.30 and 2.07 eV, respectively, which are within the desirable ranges for the water splitting. Moreover, all the considered nanomaterials were found to yield optical absorption in the visible spectrum, which is a critical feature for the employment in the solar water splitting systems. Our results furthermore confirm that the valence and conduction band edge positions in SiP, SiAs, GeP and GeAs monolayers also satisfy the requirements for the water splitting. Our results highlight the promising photocatalytic characteristics of SiP, SiAs, GeP and GeAs nanosheets for the application in solar water splitting and design of advanced hydrogen fuel cells.

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