Electronics - Page 32

A couple of months ago Cientifica raised £241,000 ($389,000) in the UK's stock exchange and the company is now public. According to press releases, Cientifica aims to acquire and build businesses that make use of graphene materials. The company will invest in by buying shares or by buying IP, assets or entering into partnerships of joint-venture arrangements.

Cientifica's CEO Tim Harper was kind enough to answer a few questions I had regarding the company's business and future plans. So first of all - congratulations Tim on the fund raising, the readmission to the AIM and on being the world's first pure-play-graphene applications public company!

Researchers from The University of Texas at Austin (UT Austin) used surface oxygen to grow centimeter-size single graphene crystals on copper. These are very large single crystals, that feature exceptional electrical properties, are about 10,000 times as large as the largest crystals made at the University only four years ago.

The researcher explain that they are controlling the growth of tiny graphene nuclei, and using Oxygen at the right surface concentration means only a few nuclei grow, and winners can grow into very large crystals. By increasing the single-crystal domain sizes, the electronic transport properties will be dramatically improved and lead to new applications in flexible electronics.

The University of Cambridge released (this was towards the end of August 2013, but I just found it now) a video showing sample transparent graphene electrodes based device prototypes:

In the video you can see a graphene touch panel used in a simple digital piano application, and also a flexible transparent display. The keyboard device is simple - when you touch the graphene electrode, the electrical charge changes which is detected by a simple electronic circuit-board connected to a speaker.

Researcher from Columbia University demonstrated that it is possible to electrically contact an atomically thin graphene (or any 2D material) only along its edge (rather than contacting it from the top). This new architecture enabled a new assembly technique that prevents interface contamination. This new assembly process resulted in the cleanest graphene ever made. They say that the new edge-contact geometry actually provides a more efficient contact without the need for complex processing.

This research work solved two graphene problems - contamination and contact. Having contacts just at the edges virtually eliminates external contamination. To achieve this breakthrough, the researchers fully encapsulated a single graphene sheet in a sandwich of thin insulating boron nitride crystals, employing a new technique in which crystal layers are stacked one-by-one.

Researchers from UC Santa Barbara are introducing a new all-graphene integrated circuit design schema. The researchers suggest a fabrication process that starts with a single-layer graphene sheet, then etches it into ribbons (which turn to semiconductors or metals, depends on the width of the ribbons) and finally metal and gate dielectric are deposited and patterned. They say this design may allow much smaller transistors and interconnects than what's possible with silicon transistors and metal interconnects. They hope this design can be realized in the "near future".

One of the big advantages of this process is that it uses just graphene to create both the semiconducting transistors and the metal interfaces. This will result in lower interface/contact resistances. The researchers presented a study with performance evaluation - those circuits achieved a 1.7 times higher signal-to-noise margin and 1-2 decades lower static power consumption over current CMOS technology.

A few days ago we reported on Bluestone Global Tech's new graphene based Field Effect Transistors. We have discussed it with BGT and have some more details on this exciting development. So first of all, we reported that the Gray-FETs are currently offered for research only, but BGT says that they are using a fab that can produce these in volume "to meet most demands". So this is suitable for commercial applications.

In fact BGT is already in talks with several academic and industrial customers. Having a standard GFET product can save a lot of time and will enable those customers to develop their own products based on these transistors faster then if they need to first develop the GFET themselves.

Bluestone Global Tech announced a new groundbreaking product today, the world's first graphene based Field Effect Transistor. BGT's Grat-FET is a wafer with 9 different GFET chips (or FET arrays), each with 64 FETs. Grat-FET is aimed towards research and development work and not for commercial production.

BGT's GFETs are fabricated (using CVD) on a silicon wafer covered with a SiO₂ layer. The high mobility (2000 cm²/Vs or more) graphene is used as the transistor channel. Each transistor consists of three terminals: source and drain metal electrodes and a global back gate.

Researchers from Columbia University managed to p-dope (remove electrons) graphene with Boron. The same researchers already showed two years ago that it is possible to n-dope (add electrons) graphene with Nitrogen atoms.

The Boron doping does not significantly modify the basic graphene structure (this is also true for Nitrogen n-doping). The researchers report that one Boron atom bonds to 3 neighboring carbon atoms, and each dopant contributes roughly half a hole (a hole is the absence of an electron).

Veeco Instruments announced that the University of Nottingham in the UK purchased two GENxplor R&D Molecular Beam Epitaxy (MBE) Systems for its School of Physics and Astronomy. The University will use the systems to grow high-quality large-area graphene and boron nitride for electronic and optoelectronic applications.

Veeco's MBE systems can deposit epitaxial graphene layers on substrates up to 3" in diameter. The company says that their vertical chamber technology enables them to build smaller MBE systems - up to 40% smaller than the competition. The MBE is an open architecture that provides convenient access to effusion cells and e-beam sources.

Last week we reported that Graphene Frontiers has been awarded a $744,600 grant from the NSF to develop and scale up their roll-to-roll graphene production. After discussing this with Graphene Frontier's CEO Michael D. Patterson, we have some more information about the company's technology and its business.

Graphene Frontier's technology was developed at the University of Pennsylvania. It is called Atmospheric Pressure CVD, or APCVD. This roll-to-roll process does not need a vacuum so it works in room pressure. The equipment required is smaller, faster and cheaper compared to CVD and this means that the manufacturing will be cost effective.