Nanoscale Carbon Based Electronic Junction Control Devices

A. Rinzler
University of Florida, US

Keywords: nanoscale electronics

Summary:

The low density of electronic states of reduced dimensionality carbons (nanotubes, graphene) implies large shifts of their chemical potential, and thus their work function, depending upon their charge state. Since the work function line-up across the interface between two materials dictates the junction transport properties, the ability to tune the work function in these systems provides a new degree of freedom for tuning electronic transport. We initially considered chemical charge transfer doping as one means to achieve such junction engineering but soon became intrigued by the idea of using field gating for an electronically tunable control over the trans-junction transport. That led to a radical redesign of the organic thin film transistor to a vertical architecture that exploits carbon nanotubes as a field gated source electrode. The architecture readily lent itself to making a vertical light emitting transistor, which has defined a new state of the art in such devices. In another direction we also realized junction control in a nanotube/n-Si Schottky junction solar cell, enhancing performance by 30%. Most recently we have begun to explore the possible advantages that graphene may have in such applications. These developments and latest progress will be discussed.