Jun 24, 2009
Self-assembled nanogaps support molecular electronics
Single-molecule devices provide a pathway to understanding the transport behavior of molecules and a possible mechanism for integrating molecular circuits in nanoelectronics. However, the fabrication of a molecular-scaled nanogap, which provides the framework for the device, can represent a significant challenge. The gap is typically a few nanometers long, which is difficult to realize with conventional micro/nanofabrication techniques.
One way around the problem is to use solution-based self-assembly, as demonstrated by researchers from the University of Copenhagen, Denmark, and Hunan University, China.
An artist's impression of the device is shown above. The molecular device was produced by self-assembly of either a single or a few rigid thiol end-capped molecules onto a gold nanoparticle connected to a conducting nanowire of doped SnO2, followed by further self-assembly of gold nanorods onto the other end of the molecules. No in situ monitoring is required during the process of device fabrication and no advanced electron-beam and other top-down nanofabrication techniques were used.
Conductive tip atomic force microscopy was employed to measure the conductance of the molecular device in the nanogap. This method overcomes some of the challenges faced in the field of molecular electronics such as bridging the gap between the single molecule length scale and the dimensions of the micro-fabricated electrodes.
The team presented its work in Nanotechnology 20 245205.
About the author
The work was performed at the University of Copenhagen, Denmark, and Hunan University, China. Prof. Thomas Bjørnholm is the director of the Nano-Science Center, University of Copenhagen. His research interests span molecular electronics, single-molecule science, nanochemistry and bionanotechnology.