Phys.org October 31, 2022 2D nanostructures based on transition-metal diborides (TMDs) are theoretically predicted to possess an exceptionally high rate and long cycling stability for Li-ion storage owing to the intrinsic presence of boron honeycomb planes and multivalent transition-metal atoms. An international team of researchers (Japan, India) investigated the Li-ion storage potential of the TMD-based nanostructure–titanium diboride (TiB2)-based hierarchical nanosheets (THNS). They demonstrated that THNS can be utilized as a high-rate anode material for Li-ion battery (LIB) and that a high discharge capacity can be obtained at a current rate of 0.025 A g1– galvanostatic charge/discharge. They demonstrated that the […]
Tag Archives: 2D materials
2D boundaries could create electricity
Science Daily August 16, 2022 The presence of piezoelectricity in 2D materials often depends on the number of layers. A team of researchers in the US (Rice University, UCLA, University of Houston, AF Laboratory Wright Patterson FB, Pennsylvania State University) made a one-dimensional, metal-semiconductor junction in a 2D heterostructure. A less than 10 nanometers thick junction was formed when tellurium gas was introduced while molybdenum metal formed a film on silicon dioxide in a chemical vapor deposition furnace. The process created islands of semiconducting molybdenum telluride phases in the sea of metallic phases. Applying voltage to the junction via the […]
Bioinspired protein creates stretchable 2D layered materials
Science Daily July 25, 2022 Protein based composites, such as nacre and bone, show astounding evolutionary capabilities, including tunable physical properties. These composites become insensitive to flaws as soon as the structural size reaches a critical length. A team of researchers in the US (Pennsylvania State University, Brown University) studied the assembly of atomistically thin inorganic sheets with genetically engineered polymeric proteins to achieve mechanically compliant and ultra-tough materials. Although bare inorganic nanosheets are brittle, they designed flexible composites with proteins, which are insensitive to flaws due to critical structural length scale (∼2 nm). These proteins, inspired by squid ring […]
Team demonstrates rare form of electricity in ultra-thin material
Phys.org April 27, 2022 Molybdenum disulfide (MoS2) is known as one of the most promising and robust 2D electronic materials. However, despite theoretical predictions, no ferroelectricity has been experimentally detected in MoS2. An international team of researchers (USA – University of Nebraska, industry, China, France, Luxembourg) has reported the experimental observation of a stable room-temperature out-of-plane polarization ordering in 2D MoS2 layers, where polarization switching is realized by mechanical pressure induced by a tip of a scanning probe microscope. Using this approach, they created the bi-domain polarization states, which exhibit different piezoelectric activity, second harmonic generation, surface potential, and conductivity. […]
A novel insulating state emerges in a 2D material
Nanowerk April 23, 2022 Within the Transition-metal dichalcogenides (TMD) family, iridium ditelluride (IrTe2) is ideally suited for the systematic study of competing factors that can affect a material’s electronic properties. An international team of researchers (USA – Lawrence Berkely National Laboratory, SLAC National Accelerator Laboratory, UC Berkeley, Sandford University, South Korea, Egypt) synthesized bilayer and monolayer IrTe2 samples and characterized their atomic and electronic structures. The analysis of the material showed that monolayer IrTe2 develops a large band gap that’s an order of magnitude larger than is typical for TMD systems, transforming the material into an insulator through the removal […]
Researchers uncover unique properties of a promising new superconductor
Science Daily June 16, 2021 An international team of researchers (USA – University of Minnesota, Pennsylvania State University, Cornell University, National High Magnetic Field Laboratory, China, Switzerland) found that Niobium diselenide (NbSe2) in 2D form is a more resilient superconductor because it has a two-fold symmetry, which is very different from thicker samples of the same material. Despite the six-fold structure, it only showed two-fold behavior in the experiment. They attributed the newly discovered two-fold rotational symmetry of the superconducting state in NbSe2 to the mixing between two closely competing types of superconductivity, namely the conventional s-wave type — typical of […]
New two-dimensional material
Science Daily April 27, 2021 An international team of researchers (USA – Carnegie Institution for Science, Howard University, University of Chicago, Argonne National Laboratory, Germany, France, Russia, Sweden, the Netherlands, China) used the laser-heated diamond anvil cell technique with pressures of up to 100 gigapascals, to synthesize a Dirac material beryllonitrene (BeN4). These are beryllium polynitrides, some of which conform to the monoclinic, others to the triclinic crystal system. The triclinic beryllium polynitrides exhibit an unusual characteristic when the pressure drops. They take on a crystal structure made up of layers. Each layer contains zigzag nitrogen chains connected by beryllium […]
UMBC team reveals possibilities of new one-atom-thick materials
EurekAlert December 15, 2020 Researchers at the University of Maryland demonstrated theoretically and experimentally that properties of two-dimensional group-III nitride semiconductors can be controlled by alloying. They found that by changing the alloying concentration, the band gap and exciton binding energies of each structure can be tuned accordingly, and for certain concentrations, a high thermoelectric performance was reported with strong dependence on the effective mass of the given alloyed monolayer. In addition, they explained contribution of each electron–hole (e-h) pair by investigating the e–h coupling strength projected on the electronic band structure. They found that the exciton binding energy decreases […]
Tailoring 2D materials to improve electronic and optical devices
Science Daily October 27, 2020 By altering the material in two different ways — atomically and physically — a team of researchers in the US (Pennsylvania, State University, MIT, Texas A&M University, Oak Ridge National Laboratory, Rutgers University) was able to enhance light emission and increase signal strength, expanding the bounds of what is possible with devices that rely on these materials. In order to strengthen the coupling, the researchers created a new type of 2D material known as Janus transition metal dichalcogenides by replacing atoms on one side of the layer with a different type of atoms, creating uneven […]
Liquid metals come to the rescue of semiconductors
EurekAlert October 11, 2020 In theory the two-dimensional materials can result in transistors that do not waste energy during their on/off switching. However, one of the barriers with the current technologies is that the deposited ultra-thin films are full of grain boundaries so that the charge carriers are bounced back from them and hence the resistive loss increases. An international team of researchers (Australia, UCLA) has developed a new method to eliminate grain boundaries using gallium metal in its liquid state. With its low melting point (29.8 deg C) its surface is atomically smooth when melted providing many free electrons […]