Working Transistor Built out of a Molecule and a few Atoms


Mon, Jul 20th, 2015 10:00 by capnasty NEWS

The the U.S. Naval Research Laboratory (NRL) announced that, together with an international team of physicists, were able to develop a working miniature transistor comprised of a single molecule and a small number of atoms using a a scanning tunnelling microscope.

The team used a highly stable scanning tunneling microscope (STM) to create a transistor consisting of a single organic molecule and positively charged metal atoms, positioning them with the STM tip on the surface of an indium arsenide (InAs) crystal. Dr. Kiyoshi Kanisawa, a physicist at NTT-BRL, used the growth technique of molecular beam epitaxy to prepare this surface. Subsequently, the STM approach allowed the researchers to assemble electrical gates from the +1 charged atoms with atomic precision and then to place the molecule at various desired positions close to the gates. Dr. Stefan Fölsch, a physicist at the PDI who led the team, explained that "the molecule is only weakly bound to the InAs template. So, when we bring the STM tip very close to the molecule and apply a bias voltage to the tip-sample junction, single electrons can tunnel between template and tip by hopping via nearly unperturbed molecular orbitals, similar to the working principle of a quantum dot gated by an external electrode. In our case, the charged atoms nearby provide the electrostatic gate potential that regulates the electron flow and the charge state of the molecule."



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