Wise Old (Owl) Chips
Graphene is a promising material for use in future transistors. It consists of one-atom-thick planar sheets, which are packed in honeycomb crystal lattice structures. The problem is that graphene doesn’t have a band gap, meaning it can’t be turned off in a system.
Rice University, Cornell University and others have devised a new, and wise, way to turn graphene into working circuits. Researchers have developed 100nm, 2D circuits using these materials. And they have also used the technology to pattern a structure in the shape of Rice’s mascot, the owl.
Researchers have combined graphene and hexagonal boron nitride (h-BN) as an insulator to make 2D circuits. With proper control, the band gap and magnetic properties of these materials can be controlled. These materials have fundamental limitations, however. And they cannot be easily integrated with conventional lithography, according to researchers.
To enable the technology, researchers have devised a “patterned regrowth” process. This enables the spatially controlled synthesis of lateral junctions between electrically conductive graphene and insulating h-BN, as well as between intrinsic and doped graphene, according to researchers.
Using chemical vapor deposition (CVD), researchers first deposited a sheet of h-BN. A mask was placed over the h-BN. The exposed material was etched away with argon gas. Then, graphene was grown via CVD in the open spaces. The hybrid layer could then be picked up and placed on any substrate.
The resulting films form continuous sheets across these hetero-junctions. At present, researchers have demonstrated 100nm technology. “It should be possible to make fully functional devices with circuits at 30, even 20 nanometers wide, all in two dimensions,” said Rice researcher Jun Lou, on the university’s Web site.
Researchers Dive Into Nano Tunnels
The Karlsruhe Institute of Technology (KIT) and Rice University claim to have dug the world’s smallest nano tunnels.
Researchers have devised metal particles, which can bore or form tunnels into graphite materials. Engineered nanoporous tunnel networks in graphite may find applications in medicine and battery technology. They also could pave the way toward nanopatterning of graphene to enable graphene nanoribbons.
In the lab, researchers devised layered carbon atoms to form graphite. The tunnels are made applying nickel nanoparticles to the graphite. These materials are heated in hydrogen gas. The surface of the metal particles serves as a catalyst removing the carbon atoms of the graphite.
Through capillary forces, the nickel particle is drawn into the hole that forms and bores through the material. The size of the tunnels obtained in the experiments was in the range of 1nm to 50nm.
On its Web site, Maya Lukas and Velimir Meded from KIT said: “The tunnels below these upper layers, however, leave atomic structures on the surface whose courses can be traced and which can be assigned to the nanotunnels by means of the very detailed scanning tunneling microscopy images and based on computerized simulations.”
Good Genes Enable Storage
The EMBL-European Bioinformatics Institute (EMBL-EBI) has devised a DNA storage technology. The technology could make it possible to store at least 100 million hours of high-definition video in a cup of DNA.
DNA is generating interest as a storage technology because of its ability to handle high-density information encoding. But previous DNA-based information storage efforts have only encoded small amounts of information.
Researchers have devised a scalable DNA storage technology. They encoded computer files totaling 739 kilobytes of hard-disk storage, with an estimated 5.2 × 106 bits into a DNA code. Researchers synthesized, sequenced and reconstructed the DNA to its original files with 100% accuracy.
“We knew we needed to make a code using only short strings of DNA, and to do it in such a way that creating a run of the same letter would be impossible. So we figured, let’s break up the code into lots of overlapping fragments going in both directions, with indexing information showing where each fragment belongs in the overall code, and make a coding scheme that doesn’t allow repeats. That way, you would have to have the same error on four different fragments for it to fail—and that would be very rare,” said Ewan Birney, associate director of EMBL-EBI, on the research group’s Web site.
In one experiment, the group sent various encoded information to Agilent Technologies. “We downloaded the files from the Web and used them to synthesize hundreds of thousands of pieces of DNA – the result looks like a tiny piece of dust,” said Emily Leproust of Agilent. In turn, Agilent mailed the sample to EMBL-EBI, where the researchers were able to sequence the DNA and decode the files without errors.