Electronics - Page 28

In December 2014, Rice University researchers designed a process (called LIG) in which a computer-controlled laser burns through a polymer to create flexible, patterned sheets of multilayer graphene that may be suitable for electronics or energy storage.

Now, their research has advanced to use the LIG process to produce 3D supercapacitors. The scientists made supercapacitors with laser-induced graphene on both sides of a polymer sheet. The sections were stacked with solid electrolytes in between, to get a multilayer construct with multiple micro-supercapacitors.

Researchers at the University of California at Riverside found a way to introduce magnetism in graphene while still preserving electronics properties. This may represent a significant step forward in the use of graphene in chips and electronics, since doping in the past induced magnetism but damaged graphene's electronic properties. this method can also be used in spintronics - chips that use electronic spin to store data.

The scientists explain they have overcome the problem by moving a graphene sheet very close to an electrical insulator with magnetic properties, since placing graphene on an insulating magnetic substrate can make the material ferromagnetic without disturbing its conductivity. The magnetic graphene is said to acquire new electronic properties, and so new quantum phenomena can take place.

Researchers at the Polish Lodz University of Technology developed a metallurgical method for producing graphene, that supplies graphene sheets of superior strength. The method relies on liquid metallic matrix and carburising gas mixture and delivers what the researchers call "HSMG" - High Strength Metallurgical Graphene.

The scientists claim this product has a higher strength and repeatability of the physico-chemical properties under varying pressure and temperature conditions, compared to currently produced graphene. They further explain that since they make graphene on liquid metal (that has a flat surface), the structure continuity is maintained and grants strength. 

Researchers at the Korean KAIST developed a technique for the delamination of single-layer graphene from a metal etching, that enables different types of transfer methods such as transfer onto a surface of a device or a curved surface, and large surface transfer onto 4 inch wafers. This method could be helpful for wearable smart gadgets and various graphene electronic devices.

While the traditional method of wet transfer might harm or contaminate the graphene in the process, this technique grants safer transfer as well as significant freedom in the transfer process. After a graphene growth substrate formed on a catalytic metal substrate is treated in an aqueous PVA solution, a PVA film is formed and a strong adhesion force is formed between the substrate and the graphene layers. The graphene is delaminated from the growth substrate by means of an elastomeric stamp while the graphene layer is in an isolated state and thus can be freely transferred onto a circuit board.

Researchers at Rice University managed to prove it possible to determine the edge properties of graphene nanoribbons by controlling the conditions under which the GNRs are pulled apart. The line-up of atoms along the edges of GNRs determines its properties - metallic or semi-conducting. These properties bear great importance for various applications, electronics being among the leading ones.  

The Rice scientists used computer modeling to demonstrate that it is possible to pull apart nanoribbons and get graphene with either pristine zigzag edges or "reconstructed zigzags" (referring to the process by which graphene atoms are shifted around to form connected rings of five and seven atoms). 

Researchers from AMO GmbH and Graphenea SE demonstrated a unique encapsulation technique that enables highly reproducible operation of graphene devices in normal atmosphere for several months. This encapsulation may help in solving one of the major problems of graphene-based devices - sensitivity to environmental elements like humidity or gases.

Researchers from the Institute of Optoelectronics & Nanomaterials at Nanjing University of Science and Technology used density functional theory computations to identify novel 2D wide band gap semiconductors called arsenene and antimonene.

The materials are typical semimetals in their natural layered state. However, monolayered arsenene and antimonene are indirect wide band gap semiconductors, and under strain they become direct band-gap semiconductors. Scientists believe that such dramatic transitions of electronic properties could bring new possibilities for nanoscale transistors with high on/off ratio, optoelectronic devices and sensors based on new ultrathin semiconductors.

Researchers at the Trinity College Dublin in Ireland discovered a method of making large quantities of black phosphorus with dimensions that can be controlled. Black phosphorus is a form of phosphorus in which phosphorus atoms form a two-dimensional sheet, which is thought to be well suited for various electronics applications as it naturally has a bandgap (among other properties).

Black phosphorus, however, is known to be hard to manufacture in large amounts, a problem which the researchers claim to have solved. The TCD researchers placed a black phosphorus lump in a liquid solvent and then bombard it with sound waves. As a result, the mass separated into a large number of nanosheets that they using a centrifuge. That resulted in high-quality nanosheets consisting of only a few layers.

Researchers at the US Department of Energy's (DOE) Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California, Berkeley, have developed a new approach for synthesizing graphene nanoribbons from pre-designed molecular building blocks. Using this process the researchers built nanoribbons that have enhanced properties (tunable bandgaps, for example) that can be potentially useful for advanced electronics.

The University of Nottingham unveiled its new Molecular Beam Epitaxy (MBE) machine, capable of reaching the high temperatures required to grow graphene and boron nitride layers on an industrial scale. This is the first machine of its kind in the world, and the researchers are hoping it will "unlock the full potential of graphene in electronics and optoelectronics".

Over £2m were invested in the design, purchase and other costs of the machine, by the Engineering and Physical Sciences Research Council, The University of Nottingham and the Leverhulme Trust. Professor Sergei Novikov, the lead scientist in this project, stresses that this is indeed a high risk project, but one that could potentially change paradigms toward growing large-area graphene and boron-nitride sheets by bonding together carbon atoms at high temperatures.