Self-driven WSe2 photodetectors enabled with asymmetrical van der Waals contact interfaces

AbstractSelf-driven photodetectors that can detect light without any external voltage bias are important for low-power applications, including future internet of things, wearable electronics, and flexible electronics. While two-dimensional (2D) materials exhibit good optoelectronic properties, the extraordinary properties have not been fully exploited to realize high-performance self-driven photodetectors. In this paper, a metal–semiconductor–metal (MSM) photodetector with graphene and Au as the two contacts have been proposed to realize the self-driven photodetector. Van der Waals contacts are formed by dry-transfer methods, which is important in constructing the asymmetrical MSM photodetector to avoid the Fermi-level pinning effect. By choosing graphene and Au as the two contact electrodes, a pronounced photovoltaic effect is obtained. Without any external bias, the self-driven photodetector exhibits a high responsivity of 7.55 A W−1 and an ultrahigh photocurrent-to-dark current ratio of ~108. The photodetector also shows gate-tunable characteristics due to the field-induced Fermi-level shift in the constituent 2D materials. What is more, the high linearity of the photodetector over almost 60 dB suggests the easy integration with processing circuits for practical applications.

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Biomechanical energy harvest based on textiles used in self-powering clothing

Journal of Engineered Fibers and Fabrics ◽

10.1177/1558925020967352 ◽

2020 ◽

Vol 15 ◽

pp. 155892502096735

Author(s):

Li Niu ◽

Xuhong Miao ◽

Gaoming Jiang ◽

Ailan Wan ◽

Yutian Li ◽

...

Keyword(s):

Flexible Electronics ◽

High Efficiency ◽

Structural Features ◽

Human Motion ◽

Energy Harvest ◽

Triboelectric Nanogenerator ◽

Wearable Electronics ◽

Practical Applications ◽

Triboelectric Nanogenerators ◽

New Generation

Advanced triboelectric nanogenerator techniques provide a massive opportunity for the development of new generation wearable electronics, which toward multi-function and self-powering. Textiles have been refreshed with the requirement of flexible electronics in recent decades. In particular, knitted-textiles have exhibited enormous and prominent potential possibilities for smart wearable devices, which are based on the merits of high stretchability, excellent elasticity, comfortability as well as compatibility. Combined knitted textiles with nanogenerator techniques will promote the knitted textile triboelectric nanogenerators (KNGs) emerging, endowing conventional textiles with biomechanical energy harvesting and sensing energy supplied abilities. However, the design of KNGs and the construction of KNGs are based on features of human motions symbolizing considerable challenges in both high efficiency and excellent comfort. Currently, this review is concerned with KNGs construction account of triboelectric effects referring to knitted-textile classifications, structural features, human motion energy traits, working mechanisms, and practical applications. Moreover, the remaining challenges of industrial production and the future prospects of knitted-textile triboelectric nanogenerators of harvesting biomechanical energy are presented.

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Anti-ambipolar and Photovoltaic effect in p-MoTe2/n-InSe Heterojunctions

Journal of Materials Chemistry C ◽

10.1039/d1tc02497c ◽

2021 ◽

Author(s):

Yiming Sun ◽

Wei Gao ◽

Xueping Li ◽

Congxin Xia ◽

Hongyu Chen ◽

...

Keyword(s):

Gate Voltage ◽

2D Materials ◽

Photovoltaic Effect ◽

Van Der Waals ◽

Two Dimensional ◽

Vdw Heterostructure ◽

Physical Phenomena

Van der Waals (vdW) heterostructure by artificially stacking different two-dimensional (2D) materials has been a promising platform to achieve diverse physical phenomena and device function. In general, the gate voltage...

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Efficient Prediction of Structural and Electronic Properties of Hybrid 2D Materials Using DFT and Machine Learning

10.26434/chemrxiv.6254756.v1 ◽

2018 ◽

Author(s):

Sherif Tawfik ◽

Olexandr Isayev ◽

Catherine Stampfl ◽

Joseph Shapter ◽

David Winkler ◽

...

Keyword(s):

Machine Learning ◽

Band Gap ◽

Density Functional ◽

2D Materials ◽

Van Der Waals ◽

Building Blocks ◽

Machine Learning Techniques ◽

Interlayer Distance ◽

Computational Screening ◽

Wide Range

Materials constructed from different van der Waals two-dimensional (2D) heterostructures offer a wide range of benefits, but these systems have been little studied because of their experimental and computational complextiy, and because of the very large number of possible combinations of 2D building blocks. The simulation of the interface between two different 2D materials is computationally challenging due to the lattice mismatch problem, which sometimes necessitates the creation of very large simulation cells for performing density-functional theory (DFT) calculations. Here we use a combination of DFT, linear regression and machine learning techniques in order to rapidly determine the interlayer distance between two different 2D heterostructures that are stacked in a bilayer heterostructure, as well as the band gap of the bilayer. Our work provides an excellent proof of concept by quickly and accurately predicting a structural property (the interlayer distance) and an electronic property (the band gap) for a large number of hybrid 2D materials. This work paves the way for rapid computational screening of the vast parameter space of van der Waals heterostructures to identify new hybrid materials with useful and interesting properties.

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Two-dimensional topological insulators exfoliated from Na3Bi-like Dirac semimetals

Physical Chemistry Chemical Physics ◽

10.1039/d1cp00736j ◽

2021 ◽

Author(s):

Xiaoqiu Guo ◽

Ruixin Yu ◽

Jingwen Jiang ◽

Zhuang Ma ◽

Xiuwen Zhang

Keyword(s):

Physical Properties ◽

Epitaxial Growth ◽

Topological Insulators ◽

2D Materials ◽

Van Der Waals ◽

Two Dimensional ◽

Dirac Semimetals

Topological insulation is widely predicted in two-dimensional (2D) materials realized by epitaxial growth or van der Waals (vdW) exfoliation. Such 2D topological insulators (TI’s) host many interesting physical properties such...

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Moiré physics in twisted van der Waals heterostructures of 2D materials

Emergent Materials ◽

10.1007/s42247-021-00270-x ◽

2021 ◽

Author(s):

Sanjay K. Behura ◽

Alexis Miranda ◽

Sasmita Nayak ◽

Kayleigh Johnson ◽

Priyanka Das ◽

...

Keyword(s):

2D Materials ◽

Van Der Waals ◽

Van Der Waals Heterostructures

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Investigation of single-domain Au silicide nanowires on Si(110) formed for Au coverages in the monolayer regime

Scientific Reports ◽

10.1038/s41598-021-94106-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Stephan Appelfeller

Keyword(s):

Fermi Level ◽

Surface Structure ◽

Density Of States ◽

The Self ◽

Single Domain ◽

Photoemission Spectroscopy ◽

Annealing Temperatures ◽

Self Organized ◽

Scanning Tunnelling ◽

Tunnelling Microscopy

AbstractThe self-organized formation of single domain Au silicide nanowires is observed on Si(110). These nanowires are analysed using scanning tunnelling microscopy (STM) and spectroscopy (STS) as well as photoemission spectroscopy (PES). Core-level PES is utilised to confirm the formation of Au silicide and establish its presence as the top most surface structure, i.e., the nanowires. The growth of the Au silicide nanowires and their dimensions are studied by STM. They form for Au coverages of about 1 monolayer and are characterized by widths of about 2 to 3 nm and heights below 1 nm while reaching lengths exceeding 500 nm when choosing appropriate annealing temperatures. Valence band PES and STS indicate a small but finite density of states at the Fermi level typical for compound metals.

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MoS2/h-BN/Graphene Heterostructure and Plasmonic Effect for Self-Powering Photodetector: A Review

Materials ◽

10.3390/ma14071672 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1672

Author(s):

Umahwathy Sundararaju ◽

Muhammad Aniq Shazni Mohammad Haniff ◽

Pin Jern Ker ◽

P. Susthitha Menon

Keyword(s):

Flexible Electronics ◽

Hexagonal Boron Nitride ◽

2D Materials ◽

Optical Power ◽

Active Regions ◽

Green Technology ◽

Plasmonic Effect ◽

Zero Bias ◽

Electrical Signals ◽

Self Powered

A photodetector converts optical signals to detectable electrical signals. Lately, self-powered photodetectors have been widely studied because of their advantages in device miniaturization and low power consumption, which make them preferable in various applications, especially those related to green technology and flexible electronics. Since self-powered photodetectors do not have an external power supply at zero bias, it is important to ensure that the built-in potential in the device produces a sufficiently thick depletion region that efficiently sweeps the carriers across the junction, resulting in detectable electrical signals even at very low-optical power signals. Therefore, two-dimensional (2D) materials are explored as an alternative to silicon-based active regions in the photodetector. In addition, plasmonic effects coupled with self-powered photodetectors will further enhance light absorption and scattering, which contribute to the improvement of the device’s photocurrent generation. Hence, this review focuses on the employment of 2D materials such as graphene and molybdenum disulfide (MoS2) with the insertion of hexagonal boron nitride (h-BN) and plasmonic nanoparticles. All these approaches have shown performance improvement of photodetectors for self-powering applications. A comprehensive analysis encompassing 2D material characterization, theoretical and numerical modelling, device physics, fabrication and characterization of photodetectors with graphene/MoS2 and graphene/h-BN/MoS2 heterostructures with plasmonic effect is presented with potential leads to new research opportunities.

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