Browse
Submit Data
Databases
API
Help

Dataset Information

15 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Armchair MoS₂ nanoribbons turned into half metals through deposition of transition-metal and Si atomic chains.

ABSTRACT: MoS₂ nanoribbons with armchair-terminated edges are semiconductors suitable for the tuning of electronic and magnetic properties. Our first-principles density function calculations reveal that a variety of transition-metal atomic chains deposited on some of the ribbons is able to transform the semiconductors into half metals, allowing transport of 100% spin-polarized currents. Furthermore, we found that a Si atomic chain is equally capable of achieving half metallicity when adsorbed on the same nanoribbon. These results should be useful for spintronic application.

SUBMITTER: Lee CH

PROVIDER: S-EPMC6127190 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Armchair MoS2 nanoribbons turned into half metals through deposition of transition-metal and Si atomic chains.

Lee Chi-Hsuan CH Lin Joy J Yang Chih-Kai CK

Scientific reports 20180906 1

MoS2 nanoribbons with armchair-terminated edges are semiconductors suitable for the tuning of electronic and magnetic properties. Our first-principles density function calculations reveal that a variety of transition-metal atomic chains deposited on some of the ribbons is able to transform the semiconductors into half metals, allowing transport of 100% spin-polarized currents. Furthermore, we found that a Si atomic chain is equally capable of achieving half metallicity when adsorbed o ...[more]

PMID: 30190601

Similar Datasets

Electronic structures of WS2 armchair nanoribbons doped with transition metals.

Project description:Armchair WS2 nanoribbons are semiconductors with band gaps close to 0.5 eV. If some of the W atoms in the ribbon are replaced by transition metals, the impurity states can tremendously affect the overall electronic structure of the doped ribbon. By using first-principles calculations based on density functional theory, we investigated substitutional doping of Ti, V, Cr, Mn, Fe, and Co at various positions on WS2 ribbons of different widths. We found that Fe-doped ribbons can have two-channel conduction in the middle segment of the ribbon and at the edges, carrying opposite spins separately. Many Co-doped ribbons are transformed into spin filters that exhibit 100% spin-polarized conduction. These results will be useful for spintronics and nanoelectronic circuit design.

| S-EPMC7536224 | biostudies-literature

Ultra-narrow metallic armchair graphene nanoribbons.

Project description:Graphene nanoribbons (GNRs)-narrow stripes of graphene-have emerged as promising building blocks for nanoelectronic devices. Recent advances in bottom-up synthesis have allowed production of atomically well-defined armchair GNRs with different widths and doping. While all experimentally studied GNRs have exhibited wide bandgaps, theory predicts that every third armchair GNR (widths of N=3m+2, where m is an integer) should be nearly metallic with a very small bandgap. Here, we synthesize the narrowest possible GNR belonging to this family (five carbon atoms wide, N=5). We study the evolution of the electronic bandgap and orbital structure of GNR segments as a function of their length using low-temperature scanning tunnelling microscopy and density-functional theory calculations. Already GNRs with lengths of 5?nm reach almost metallic behaviour with ?100?meV bandgap. Finally, we show that defects (kinks) in the GNRs do not strongly modify their electronic structure.

| S-EPMC4682157 | biostudies-literature

Charge transport mechanism in networks of armchair graphene nanoribbons.

Project description:In graphene nanoribbons (GNRs), the lateral confinement of charge carriers opens a band gap, the key feature that enables novel graphene-based electronics. Despite great progress, reliable and reproducible fabrication of single-ribbon field-effect transistors (FETs) is still a challenge, impeding the understanding of the charge transport. Here, we present reproducible fabrication of armchair GNR-FETs based on networks of nanoribbons and analyze the charge transport mechanism using nine-atom wide and, in particular, five-atom-wide GNRs with large conductivity. We show formation of reliable Ohmic contacts and a yield of functional FETs close to unity by lamination of GNRs to electrodes. Modeling the charge transport in the networks reveals that transport is governed by inter-ribbon hopping mediated by nuclear tunneling, with a hopping length comparable to the physical GNR length. Overcoming the challenge of low-yield single-ribbon transistors by the networks and identifying the corresponding charge transport mechanism is a key step forward for functionalization of GNRs.

| S-EPMC7005326 | biostudies-literature

Direct oriented growth of armchair graphene nanoribbons on germanium.

Project description:Graphene can be transformed from a semimetal into a semiconductor if it is confined into nanoribbons narrower than 10?nm with controlled crystallographic orientation and well-defined armchair edges. However, the scalable synthesis of nanoribbons with this precision directly on insulating or semiconducting substrates has not been possible. Here we demonstrate the synthesis of graphene nanoribbons on Ge(001) via chemical vapour deposition. The nanoribbons are self-aligning 3° from the Ge?110? directions, are self-defining with predominantly smooth armchair edges, and have tunable width to <10?nm and aspect ratio to >70. In order to realize highly anisotropic ribbons, it is critical to operate in a regime in which the growth rate in the width direction is especially slow, <5?nm?h(-1). This directional and anisotropic growth enables nanoribbon fabrication directly on conventional semiconductor wafer platforms and, therefore, promises to allow the integration of nanoribbons into future hybrid integrated circuits.

| S-EPMC4918381 | biostudies-literature

Spatially resolved electronic structures of atomically precise armchair graphene nanoribbons.

Project description:Graphene has attracted much interest in both academia and industry. The challenge of making it semiconducting is crucial for applications in electronic devices. A promising approach is to reduce its physical size down to the nanometer scale. Here, we present the surface-assisted bottom-up fabrication of atomically precise armchair graphene nanoribbons (AGNRs) with predefined widths, namely 7-, 14- and 21-AGNRs, on Ag(111) as well as their spatially resolved width-dependent electronic structures. STM/STS measurements reveal their associated electron scattering patterns and the energy gaps over 1 eV. The mechanism to form such AGNRs is addressed based on the observed intermediate products. Our results provide new insights into the local properties of AGNRs, and have implications for the understanding of their electrical properties and potential applications.

| S-EPMC3523290 | biostudies-literature

Combinatorial growth of Si nanoribbons.

Project description:Silicon nanoribbons (Si NRs) with a thickness of about 30 nm and a width up to a few micrometers were synthesized. Systematic observations indicate that Si NRs evolve via the following sequences: the growth of basal nanowires assisted with a Pt catalyst by a vapor-liquid-solid (VLS) mechanism, followed by the formation of saw-like edges on the basal nanowires and the planar filling of those edges by a vapor-solid (VS) mechanism. Si NRs have twins along the longitudinal < 110 > growth of the basal nanowires that also extend in < 112 > direction to edge of NRs. These twins appear to drive the lateral growth by a reentrant twin mechanism. These twins also create a mirror-like crystallographic configuration in the anisotropic surface energy state and appear to further drive lateral saw-like edge growth in the < 112 > direction. These outcomes indicate that the Si NRs are grown by a combination of the two mechanisms of a Pt-catalyst-assisted VLS mechanism for longitudinal growth and a twin-assisted VS mechanism for lateral growth.

| S-EPMC3211989 | biostudies-literature

Efficient MoWO3/VO2/MoS2/Si UV Schottky photodetectors; MoS2 optimization and monoclinic VO2 surface modifications.

Project description:The distinctive properties of strongly correlated oxides provide a variety of possibilities for modulating the properties of 2D transition metal dichalcogenides semiconductors; which represent a new class of superior optical and optoelectronic interfacing semiconductors. We report a novel approach to scaling-up molybdenum disulfide (MoS2) by combining the techniques of chemical and physical vapor deposition (CVD and PVD) and interfacing with a thin layer of monoclinic VO2. MoWO3/VO2/MoS2 photodetectors were manufactured at different sputtering times by depositing molybdenum oxide layers using a PVD technique on p-type silicon substrates followed by a sulphurization process in the CVD chamber. The high quality and the excellent structural and absorption properties of MoWO3/VO2/MoS2/Si with MoS2 deposited for 60 s enables its use as an efficient UV photodetector. The electronically coupled monoclinic VO2 layer on MoS2/Si causes a redshift and intensive MoS2 Raman peaks. Interestingly, the incorporation of VO2 dramatically changes the ratio between A-exciton (ground state exciton) and trion photoluminescence intensities of VO2/(30 s)MoS2/Si from <?1 to >?1. By increasing the deposition time of MoS2 from 60 to 180 s, the relative intensity of the B-exciton/A-exciton increases, whereas the lowest ratio at deposition time of 60 s refers to the high quality and low defect densities of the VO2/(60 s)MoS2/Si structure. Both the VO2/(60 s)MoS2/Si trion and A-exciton peaks have higher intensities compared with (60 s) MoS2/Si structure. The MoWO3/VO2/(60 s)MoS2/Si photodetector displays the highest photocurrent gain of 1.6, 4.32?×?108 Jones detectivity, and?~?1.0?×?1010 quantum efficiency at 365 nm. Moreover, the surface roughness and grains mapping are studied and a low semiconducting-metallic phase transition is observed at?~?40 °C.

| S-EPMC7522211 | biostudies-literature

Lateral Fusion of Chemical Vapor Deposited N = 5 Armchair Graphene Nanoribbons.

Project description:Bottom-up synthesis of low-bandgap graphene nanoribbons with various widths is of great importance for their applications in electronic and optoelectronic devices. Here we demonstrate a synthesis of N = 5 armchair graphene nanoribbons (5-AGNRs) and their lateral fusion into wider AGNRs, by a chemical vapor deposition method. The efficient formation of 10- and 15-AGNRs is revealed by a combination of different spectroscopic methods, including Raman and UV-vis-near-infrared spectroscopy as well as by scanning tunneling microscopy. The degree of fusion and thus the optical and electronic properties of the resulting GNRs can be controlled by the annealing temperature, providing GNR films with optical absorptions up to ?2250 nm.

| S-EPMC5860786 | biostudies-literature

Atomic threshold-switching enabled MoS2 transistors towards ultralow-power electronics.

Project description:Power dissipation is a fundamental issue for future chip-based electronics. As promising channel materials, two-dimensional semiconductors show excellent capabilities of scaling dimensions and reducing off-state currents. However, field-effect transistors based on two-dimensional materials are still confronted with the fundamental thermionic limitation of the subthreshold swing of 60 mV decade-1 at room temperature. Here, we present an atomic threshold-switching field-effect transistor constructed by integrating a metal filamentary threshold switch with a two-dimensional MoS2 channel, and obtain abrupt steepness in the turn-on characteristics and 4.5 mV decade-1 subthreshold swing (over five decades). This is achieved by using the negative differential resistance effect from the threshold switch to induce an internal voltage amplification across the MoS2 channel. Notably, in such devices, the simultaneous achievement of efficient electrostatics, very small sub-thermionic subthreshold swings, and ultralow leakage currents, would be highly desirable for next-generation energy-efficient integrated circuits and ultralow-power applications.

| S-EPMC7719160 | biostudies-literature

Atomic Structure and Dynamics of Defects in 2D MoS2 Bilayers.

Project description:We present a detailed atomic-level study of defects in bilayer MoS2 using aberration-corrected transmission electron microscopy at an 80 kV accelerating voltage. Sulfur vacancies are found in both the top and bottom layers in 2H- and 3R-stacked MoS2 bilayers. In 3R-stacked bilayers, sulfur vacancies can migrate between layers but more preferably reside in the (Mo-2S) column rather than the (2S) column, indicating more complex vacancy production and migration in the bilayer system. As the point vacancy number increases, aggregation into larger defect structures occurs, and this impacts the interlayer stacking. Competition between compression in one layer from the loss of S atoms and the van der Waals interlayer force causes much less structural deformations than those in the monolayer system. Sulfur vacancy lines neighboring in top and bottom layers introduce less strain compared to those staggered in the same layer. These results show how defect structures in multilayered two-dimensional materials differ from their monolayer form.

| S-EPMC6641595 | biostudies-literature