Researchers from NIST and Sandia have published a detailed review of electrical contacts in one and two-dimensional nanomaterials. They explain that existing models of electrical contacts in bulk semiconductor devices are not applicable at the nanoscale. New models are needed to understand contact formation and charge transport in nanosystems.
The review highlights the unusual physics and material science of electrical contacts to nanostructures. Conventional contacts have a planar interface, but nanocontacts have multiple possible geometries with unique properties. The kinetics and thermodynamics of metal/nanostructure interfaces differ from those of the bulk due to their small lateral dimensions and the ability of nanostructures to accommodate strain.
The researchers provide three examples of different nanomaterial contacts:
1. Abrupt epitaxial silicide/silicon nanowire junctions with novel orientations can be formed at lower temperatures than thin metal films, offering opportunities for new devices like metal source-drain MOSFETs and SpinFETs.
2. Metal contacts to carbon nanotubes can result in electrically transparent graphene-CNT contacts through catalytic carbonization of the interface.
3. Making low resistance ohmic contacts to semiconductor nanowires has proven challenging and requires new understanding of doping at the nanometer scale.
The researchers conclude that better understanding of the basic science of nanoscale contacts is necessary to allow nanoscale materials to be incorporated into useful new device designs.
Keywords: Nanoscale, Electrical Contacts, Nanostructures, Charge Transport, Nanomaterials
