Could be applied to solar cells, ultracapacitors for energy storage, or advanced transistors for energy efficient electronics, among many other applications
Researchers at Penn State’s Center for 2-Dimensional and Layered Materials and the University of Texas at Dallas have shown the ability to grow high quality, single-layer materials one on top of the other using chemical vapor deposition. This highly scalable technique, often used in the semiconductor industry, can produce new materials with unique properties that could be applied to solar cells, ultracapacitors for energy storage, or advanced transistors for energy efficient electronics, among many other applications.
“People have been trying to stack these layered materials using the scotch tape method (an exfoliation method developed by Nobel laureates Novoselov and Geim to produce graphene), but that leaves residue on the layers and is not scalable,” explains Joshua Robinson of Penn State, corresponding author on a recent article published online in ACS Nano. Other groups have utilized the chemical vapor deposition method to grow layered materials on a copper substrate, but this method requires some sophisticated techniques to transfer the layered material to a more functional substrate without causing tears or contamination.
Robinson and his colleagues employed a more direct method, using chemical vapor deposition to grow a layer of quasi-free-standing epitaxial graphene (QFEG) on a silicon carbide substrate, followed by a layer of molybdenum disulfide (MoS2), a metal dichalcogenide compound widely used as a lubricant. In order to test the quality of the MoS2 on graphene, the researchers used the material to build a photodetector device to measure the layered material’s efficiency at converting photons to electrons. They found that the response of the MoS2/QFEG material was 100 times higher than MoS2 alone.
For devices, the QFEG method, which introduces a layer of hydrogen atoms between the substrate and the graphene and thereby decouples the graphene layer from the underlying silicon carbide, proved to be a better choice than the more standard as-grown graphene. Robinson says, “In general QFEG is more interesting, and from a device point of view, it’s critical.”
To see if quasi-free-standing graphene was a suitable template for the growth of other artificially stacked atomic layers, the team synthesized two other van der Waals solids: tungsten diselenide, and hexagonal boron nitride. (van der Waals solids have strong in-plane bonding but weak interlayer bonding.) They determined that epitaxial graphene was “an excellent candidate for building large-area vdW solids that will have extraordinary properties and performances.”
Industry has already shown strong interest in 2D layered materials for RF applications, low-power and low-cost semiconductors, and for displays on flexible substrates. “This is the first step,” Robinson says. “To truly control properties we will need to look at a variety of these systems that should turn out to have entirely new properties when stacked together.”
The Latest on: 2D layered materials
via Google News
The Latest on: 2D layered materials
- New platform generates hybrid light-matter excitations in highly charged grapheneon December 2, 2020 at 10:03 am
Columbia University researchers report that they have achieved plasmonically active graphene with record-high charge density without an external gate. They accomplished this by exploiting novel ...
- Graphene Markets: Orders Arrive, Consolidation Awaits, Reports IDTechExon December 2, 2020 at 9:42 am
Following decades of development, 2021 and 2022 are set to be notable years for the graphene industry, as it finally approaches an ...
- New family of quasiparticles appears in grapheneon November 30, 2020 at 9:56 am
Telltale traces Researchers at the University of Manchester in the UK have identified a new family of quasiparticles in superlattices made from graphene sandwiched between two slabs of boron nitride.
- Hydrogel e-skin stretches sensory limitson November 30, 2020 at 3:12 am
The emergence of 2D sensors has accelerated efforts to integrate these atomically thin, mechanically strong materials into functional, durable artificial skins.” The hydrogel layer of the KAUST e-skin ...
- ‘Electronic skin’ can be used to collect biological data in real time: Studyon November 29, 2020 at 9:41 pm
A material that is identical to human ... “as a strong and stretchy substrate and a 2D titanium carbide MXene as the sensing layer, bound together with highly conductive nanowires.” ...
- MRS combines Spring and Fall meetings into virtual eventon November 24, 2020 at 10:45 am
Photoluminescent 2D perovskites have a direct bandgap with a narrow emission peak that can be tuned by changing the layer thickness and the material composition, and have been widely studied for ...
- What Methodology Best Fits 2D-Material Fabrication?on November 23, 2020 at 4:00 pm
Coleman said that among many types of 2D materials, black phosphorus (or phosphorene) seems to have captured people’s interest (see the table). It’s a single layer of phosphorus, and has a ...
- Abnormal conductivity in low-angle twisted bilayer grapheneon November 20, 2020 at 1:40 pm
The incommensurate state of the twisted interface between adjacent layers typically leads to suppression of ... force microscopy (c-AFM), where the interlayer conductivity of 2D material is coupled ...
- Staying ahead of the curve with 3D curved grapheneon November 20, 2020 at 9:41 am
A team of researchers has amplified 3D graphene's electrical properties by controlling its curvature. "Our research showed the conservation and the degradation of the ultra-low dissipative transport ...
- Curved 3D graphene offers amplified electrical propertieson November 20, 2020 at 8:36 am
A team of researchers has amplified 3D graphene's electrical properties by controlling its curvature. The team, from Tohoku University in Japan, set out to improve graphene’s electric transport ...
via Bing News