Semiconductor nanogaps for the fabrication of molecular electronic devices

Other conference contribution, 2001

Recent results from the groups of Reed and Heath have shown that it is possible to obtain negative differential resistance and memory effects in molecular electronic devices by depositing electrodes on top of monolayers of organic molecules. For integration with existing technology, however, it is preferable to deposit molecules into nanometre-sized gaps preformed on a substrate. We have developed new methods to produce these gaps without the need to perform lithography at the nanometre scale. The nanometre spacing is defined by the vertical thickness of the oxide layer in a metal-oxide-semiconductor structure, or by the height of an insulating layer in an MBE-grown semiconductor heterostructure. Selective removal of the insulating layer provides a gap into which semiconductor nanocrystals or conjugated molecules may be assembled. We present characterisation of the semiconductor nanogaps, and initial electrical measurements on semiconductor nanocrystals deposited in the gaps.