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Showing 1 to 20 of 38 for “"WSe2"”.
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Electrical, electronic and optical properties of MoSe2 and WSe2
Transition-metal dichalcogenides (TMDC) crystals have emerged as a new class of semiconductors that display distinctive properties at monolayer thickness. Their electrical, electronic and optical properties are of particular interest and importance for applications in optoelectronics as light …
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SYNTHESIS, ELECTRONIC AND OPTO-ELECTRONIC TRANSPORT PROPERTIES OF ATOMICALLY THIN 2D LAYERS OF MoS2, WSe2 and CuIn7Se11
… as well as CVT grown mechanically exfoliated WSe2 and ternary alloy of CuIn7Se11 is reported. Specifically, it is shown that in case of MoS2, the ac conductance (σ(ω); measured in the range of 10mHz < ω < 0.1 MHz) of atomically thin 2D layers of chemical vapor deposited (CVD) Molybdenum …
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Ultrafast Charge and Energy transfer Dynamics in Organic-Transition Metal Dichalcogenides Heterostructures
… namely Pentacene/MoTe2 and Pentacene/WSe2 were examined. It was found that excitation at the electronic gap of MoTe2 leads to a Type II to type I band alignment cross over in Pentacene/MoTe2 heterostructure, due to a mechanism known as carrier-driven bandgap renormalization. Triplet …
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Electrical properties of metal/wse2structures
… metal contacts on two-Dimensional layer (2-D) of WSe2 is a big challenge. In this research, a comparative study is presented on the electrical properties of metal/WSe2 Schottky barrier diodes with various metals such as Au, In, Al, and Ga in the temperature range of 80K to 400K well within the …
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Optical investigation of many-body interactions in transition metal dichalcogenide heterostructures
… monolayer and bilayer tungsten diselenide (WSe2) and molybdenum diselenide (MoSe2) are investigated under varying carrier concentration. The doping dependent dispersions of the exciton-polarons are shown to be excellent probes of the distinctive band structures of these materials. Then, in a …
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Synthesis and characterization of two-dimensional transition metal dichalcogenides
… investigated the growth of MoS2 and WSe2 using chemical vapor deposition (CVD) and metal-organic chemical vapor deposition (MOCVD) methods. I studied the impact of the growth conditions, including temperature, pressure, gas flow rate, precursor type, precursor quantify, the position …
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High-throughput characterisation and device integration of nanomaterials
… nanowires, bilayer graphene, MoS2, and MoSe2/WSe2 lateral heterostructures. First, a novel method for nanofabrication is introduced using a lithography-optimised fiducial marker system LithoTag, which is used for the identification of individual InAs nanowires and for automatically designing …
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Probing valley and magnetic photoexcitations in 2D crystals and their heterostructures
… probe of excitons and trions in monolayer WSe2 and demonstrate an electrical exciton-based second-harmonic generation switch. We then add MoSe2 to the picture, forming MoSe2/WSe2 heterobilayers in which we reveal the valley-contrasting physics of long-lived free and trapped interlayer …
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OPTICAL PROPERTIES OF 2D TRANSITION METAL DICHALCOGENIDES ENHANCED BY PLASMONIC NANOSTRUCTURES
… (TMDCs) such as tungsten diselenide (WSe2) and molybdenum disulfide (MoS2) have impressive properties arising from the atomically-thin nature and have been demonstrated to be potentially useful building blocks for optoelectronic integrated circuits. An important research focus on TMDCs …
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Optics and Optoelectronics of Atomically Thin Magnets and Semiconductors
… CrI3, and monolayer flakes of semiconducting WSe2. The first three chapters of this thesis focus on the isolation, characterization, and control of magnetism in mono- and few-layer flakes of CrI3. Bulk crystals of CrI3 are known to be ferromagnetic insulators with large predicted …
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Computational Study of Two-Dimensional Materials for Energy Applications
… vdWs heterostructures based on C60/hBN and C60/WSe2 are examined. Professor Zhenan Bao of Stanford University used high-resolution scanning tunnelling electron microscopy and selective area electron diffraction to reveal a single crystal-like structure of C60 molecules on a hBN substrate. A …
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Ultra low thermal conductivity in layered disordered crystalline materials
… thermal conductivity of thin films of WSe2 is as small as 0.05 W m-1 K-1 at room temperature, 30 times smaller than the c-axis thermal conductivity of single-crystal WSe2 and a factor of 6 smaller than the predicted minimum thermal conductivity for this material. The ultralow thermal …
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Resonance fluorescence of novel quantum emitters
… excitons believed to be localized on defects in WSe2 monolayers are investigated using optical spectroscopy and resonance fluorescence (RF). The development of light sources emitting around 1300 nm is motivated primarily by the possibility of their use in information communication applications. …
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Enhancing the Light output of Solid State Emitters
… It was found that for Tungsten Diselenide (WSe2) the solid immersion lens increased the intensity of the emitted photoluminescence, as well as preventing the monolayer from degrading. This method could prove to be an excellent method for increasing the light output of 2D material based …
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Electronic devices based on semiconducting transition metal dichalcogenides
… properties of CVD synthesized monolayer MoS2 and WSe2 are investigated. The mobilities are extracted from back gate transistors, where the contact resistance is excluded with 4-point measurement for MoS2, and the histogram of mobilities is summarized for WSe2. Three different device structures …
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Electrical contacts on two-dimensional transition metal dichalcogenide semiconductors
… on atomically thin 2D MoS2, WS2, NbS2 and WSe2. Using electronic measurements, I have demonstrated that the contact resistance of indium electrodes is ~ 3000 Ω·µm for single layer and ~ 800 Ω·µm for few layered MoS2 – amongst the lowest observed for 3D metal electrodes evaporated on MoS2 …
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Electronic transport in atomically thin layered materials
… on graphene and the dichalcogenides MoS 2 and WSe2. Initially, we expand on the family of exciting graphene devices with new work in the fabrication and characterization of suspended graphene nanoelectromnechanical resonators. Here we will demonstrate novel suspension techniques for graphene …
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Coherent light-matter interactions in monolayer transition-metal dichalcogenides
… dichalcogenides (TMDs) such as MoS 2, WS2 and WSe2 are prime examples of such semiconductors. They appear in layered structure that can be reduced to a stable single layer where remarkable electronic properties can emerge. Monolayer TMDs have a pair of electronic valleys which have been …
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Studying magnetic and 3D atomic structure using 4D scanning transmission electron microscopy
… achieve MEP reconstructions of twisted bilayer WSe2 with sub-nanometer depth resolution, which allowed us to extract 3D atomic coordinates. Furthermore, by incorporating prior knowledge about the structure of WSe2, we were able to refine the coordinates from ptychography to reach picometer-scale …
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Understanding and engineering electronic and optoelectronic properties of 2D materials and their interfaces
… photodiodes based on a lateral in-plane MoS2-WSe2 heterojunctions, and (3) interfacial properties and (opto)electronic characteristics of a phosphorene-MoS2 vertical vdW p-n junction. The first part of this thesis explores the layer number dependent electrical characteristics of the MoS2-metal …
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