A5009096098- 2D Materials and Applications
- Graphene research and applications
- Plasmonic and Surface Plasmon Research
- Photonic and Optical Devices
- MXene and MAX Phase Materials
- Molecular Junctions and Nanostructures
- Nanowire Synthesis and Applications
- Diamond and Carbon-based Materials Research
- Advanced Fiber Laser Technologies
- Advanced Memory and Neural Computing
- Ferroelectric and Negative Capacitance Devices
- Inorganic Chemistry and Materials
- Quantum Dots Synthesis And Properties
- Perovskite Materials and Applications
- Advancements in Semiconductor Devices and Circuit Design
- Analytical Chemistry and Sensors
- Electronic and Structural Properties of Oxides
- Topological Materials and Phenomena
- Ga2O3 and related materials
- Organic and Molecular Conductors Research
- Laser-Matter Interactions and Applications
- Chalcogenide Semiconductor Thin Films
- Mechanical and Optical Resonators
- Luminescence and Fluorescent Materials
- Thermal properties of materials
TU Wien
2012-2018
Massachusetts Institute of Technology
2017
Photonics (United States)
2017
University of Applied Sciences Technikum Wien
2015
There is an increasing interest in using graphene (1, 2) for optoelectronic applications. (3-19) However, because inherently weak optical absorber (only ≈2.3% absorption), novel concepts need to be developed increase the absorption and take full advantage of its unique properties. We demonstrate that by monolithically integrating with a Fabry-Pérot microcavity, 26-fold enhanced, reaching values >60%. present graphene-based microcavity photodetector responsivity 21 mA/W. Our approach can...
Semiconductor heterostructures form the cornerstone of many electronic and optoelectronic devices are traditionally fabricated using epitaxial growth techniques. More recently, have also been obtained by vertical stacking two-dimensional crystals, such as graphene related materials. These layered designer materials held together van der Waals forces contain atomically sharp interfaces. Here, we report on a type-II heterojunction made molybdenum disulfide tungsten diselenide monolayers. The...
Atomically thin transition metal dichalcogenides have emerged as promising candidates for sensitive photodetection. Here, we report a photoconductivity study of biased mono- and bilayer molybdenum disulfide field-effect transistors. We identify photovoltaic photoconductive effects, which both show strong photogain. The effect is described shift in transistor threshold voltage due to charge transfer from the channel nearby molecules, including SiO2 surface-bound water. attributed trapping...
Two-dimensional van der Waals materials have emerged as promising platforms for solid-state quantum information processing devices with unusual potential heterogeneous assembly. Recently, bright and photostable single photon emitters were reported from atomic defects in layered hexagonal boron nitride (hBN), but controlling inhomogeneous spectral distribution reducing multi-photon emission presented open challenges. Here, we demonstrate that strain control allows tunability of hBN over 6...
The commonly observed hysteresis in the transfer characteristics of MoS2 transistors is typically associated with charge traps gate insulator. Since Si technologies such can lead to severe reliability issues, we perform a combined study both as well arguably most important issue, bias-temperature instability. We use single-layer FETs SiO2 and hBN insulators demonstrate that phenomena are indeed due insulator time constants distributed over wide timescales, where faster ones slower...
Strain engineering is widely used in material science to tune the (opto-)electronic properties of materials and enhance performance devices. Two-dimensional atomic crystals are a versatile playground study influence strain, as they can sustain very large deformations without breaking. Various optical techniques have been employed probe strain two-dimensional materials, including micro-Raman photoluminescence spectroscopy. Here we demonstrate that second harmonic generation constitutes an...
The peculiar nature of light-matter interaction in atomically thin transition metal dichalcogenides is recently under examination for application novel optoelectronic devices. Here, we show that heterostructures composed two or more such layers can be used solar energy harvesting. strong absorption these makes it possible to achieve an efficient power conversion with a minimal amount active material. We describe detail different fabrication techniques allow realize clean, sharp interfaces....
The performance of MoS2 transistors is strongly affected by charge trapping in oxide traps with very broad distributions time constants. These defects degrade the mobility and additionally lead to hysteresis gate transfer characteristics, which presents a crucial reliability issue for these new technologies. Here we perform detailed study double-gated FETs show that this nothing else than combination threshold voltage shifts resulting from positive negative bias-temperature instabilities....
Even though the hysteresis in gate transfer characteristics of two-dimensional (2D) transistors is a frequently encountered phenomenon, physics behind it are up to now only barely understood, let alone modeled. Here, we demonstrate that phenomenon can be captured accurately by previously established non-radiative multiphonon model describing charge capture and emission events surrounding dielectrics. The embedded into drift-diffusion based TCAD simulation environment, which was adapted 2D...
Abstract Heterostructures based on atomically thin semiconductors are considered a promising emerging technology for the realization of ultrathin and ultralight photovoltaic solar cells flexible substrates. Much progress has been made in recent years technological level, but clear picture physical processes that govern response remains elusive. Here, we present device model is able to fully reproduce current–voltage characteristics type-II van der Waals heterojunctions under optical...
Graphene shows great potential for optoelectronic applications but suffers from rather weak interaction with light due its single-atomic thickness. Here, we report the enhanced of graphene and Raman transitions using localized surface plasmons. The plasmons are generated in silver nanoislands that fabricate by simple means metal deposition on top graphene. Despite broad size distribution nanoislands, find a 100-fold enhancement signal. We provide an analytical model description optical...
We study electric field modulation of the thermovoltage in single-layer MoS2. The Seebeck coefficient generally increases for a diminishing free carrier concentration, and case MoS2 reaches considerable large values about S = −5160 μV/K at resistivity 490 Ω m. Further, we observe time dependent degradation conductivity single layer MoS2, resulting variations coefficient. is attributable to adsorbates from ambient air, acting as p-dopants additional Coulomb potentials, scattering increase,...
We present photoconductivity studies of metal/graphene interfaces, discuss the origin photoconductive behavior, and ultrafast photocurrent measurements. Conversion surface plasmon polaritons into electrical current at interfaces will also be presented. Based on these findings we developed several concepts for graphenebased photodetectors. One involves deposition inter-digitated metal electrodes graphene to realize a metal-graphene-metal photodetector. used this device demonstrate faithful...
The electrical characteristics of field-effect transistors based on 2D materials such as MoS2 strongly depend defects in various regions the device. Thus, an accurate description charge transfer reactions with is essential they have a strong impact several important performance parameters. In particular, disturb electrostatic control gate over channel, which one central advantages devices ultimate scaling limit. As consequence trapping these defects, large threshold voltage shifts are...
We perform a detailed reliability study of MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , MoSe MoTe and WS field-effect transistors fabricated on the same SiO /Si substrate. First we analyze sensitivity these devices to adsorbate-type trapping sites top channel show that their contribution can be minimized at high temperatures, which leads domination charge by oxide traps. Then compare high-temperature dynamics hysteresis...
We present the realization and optoelectronic characterization of p-n junctions based on two-dimensional semiconductors. Such may be realized by lateral or vertical arrangement atomically thin p-type n-type materials. In particular, a WSe<sub>2</sub> monolayer junction, formed electrostatic doping using pair split gate electrodes, MoS<sub>2</sub>/WSe<sub>2</sub> van der Waals type-II heterojunction are presented. Upon optical illumination, conversion light into electrical energy occurs in...
The hysteresis in the gate transfer characteristics of transistors made two-dimensional materials is one most obvious problems this novel technology. Here we attempt for first time to develop a physical modeling approach describing devices based on materials. Our model drift-diffusion TCAD simulation coupled previously established non-radiative multiphonon charge capture and emission events surrounding dielectrics, which are considered main cause observed hysteresis. We validate our against...
We study the hysteresis and bias-temperature instabilities in single-layer MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> FETs with SiO hBN gate insulators attempt to capture correlation between these phenomena. In agreement previous literature reports, our results show that use of as a insulator reduces hysteresis. Furthermore, we impact is weaker for /hBN transistors. However, at higher temperature reliability reduced due...
Get PDF Email Share with Facebook Tweet This Post on reddit LinkedIn Add to CiteULike Mendeley BibSonomy Citation Copy Text T. Mueller, M. Furchi, A. Zechmeister, S. Schuler, and Pospischil, "Atomically-thin van der Waals Heterostructure Solar Cells," in CLEO: 2015, OSA Technical Digest (online) (Optica Publishing Group, 2015), paper FTh3E.2. Export BibTex Endnote (RIS) HTML Plain alert Save article
Electronic and photonic devices based on two-dimensional (2D) atomic crystals, such as graphene layered transition-metal dichalcogenides (TMDCs), are perceived potential candidates to complement, or even replace, conventional semiconductor in various applications. 2D crystals of high material quality stability, so, they can be produced with large-area dimensions at low cost. Moreover, the possibility stacking different atomically-thin layers top each other provides opportunity creating...