An etching process based on a three-layer stack achieves transfer into silicon of patterns with a depth of less than 5nm and a half-pitch of less than 20nm written by thermal scanning probe lithography.
Read more
A major goal in renewable energy research is to harvest the energy of the sun to convert water into hydrogen gas, a storable fuel. Now, with a nanoparticle-based system, researchers have set a record for one of the half-reactions in this process, reporting 100% efficiency for the reduction of water to hydrogen (Nano Lett. 2016, DOI: 10.1021/acs.nanolett.5b04813).
To make such water-splitting systems, researchers must find the right materials to absorb light and catalyze the splitting of water into hydrogen and oxygen. The two half-reactions in this process—the reduction of water to hydrogen gas, and the oxidation of water to oxygen gas—must be isolated from each other so their products don’t react and explode. “Completing the cycle in an efficient, stable, safe fashion with earth-abundant elements is an ongoing challenge,” says chemist Nathan S. Lewis of Caltech, who was not involved in this study.
Until recently, the efficiency of the reduction step had maxed out at 60%. One challenge is that electrons and positive charges formed in the light absorption process can rapidly recombine, preventing the electrons from reducing water molecules to form hydrogen. To overcome this problem, several years ago, Lilac Amirav of Technion–Israel Institute of Technology and her colleagues designed a nanoparticle-based system (J. Phys. Chem. Lett. 2010, DOI: 10.1021/jz100075c) that would physically separate the charges formed during photocatalysis.
Read more
Astronomers have found an extraordinary trail of gas greater than 300,000 light years across originating from a nearby galaxy called NGC 4569, according to a report in Astronomy & Astrophysics.
The tail is comprised of hydrogen gas, the material new stars are born from, and is five times longer than the galaxy itself.
Read more
Physicists have zoomed in on the transition that could explain why copper-oxides have such impressive superconducting powers.
Settling a 20-year debate in the field, they found that a mysterious quantum phase transition associated with the termination of a regime called the “pseudogap” causes a sharp drop in the number of conducting electrons available to pair up for superconductivity. The team hypothesizes that whatever is happening at this point is probably the reason that cuprates support superconductivity at much higher temperatures than other materials—about half way to room temperature.
“It’s very likely that the reason superconductivity grows in the first place, and the reason it grows so strongly, is because of that critical point,” CIFAR Senior Fellow Louis Taillefer (Université de Sherbrooke) says. The new findings are published in Nature.
Read more
Breaking the bacteria barriers.
If that field is at just the right magnitude, it will open up pores within the cell membrane, through which DNA can flow. But it can take scientists months or even years to figure out the exact electric field conditions to reversibly unlock a membrane’s pores.
A new microfluidic device developed by MIT engineers may help scientists quickly home in on the electric field “sweet spot” — the range of electric potentials that will harmlessly and temporarily open up membrane pores to let DNA in. In principle, the simple device could be used on any microorganism or cell, significantly speeding up the first step in genetic engineering.
“We’re trying to reduce the amount of experimentation that’s needed,” said Cullen Buie, the Esther and Harold E. Edgerton Associate Professor of mechanical engineering at MIT. “Our big vision for this device and future iterations is to be able to take a process that usually takes months or years, and do it in a day or two.”
Read more
