Electronically Tunable Nanostructures: Metals and Conducting Oxides

Abstract

Electric field-induced reversible tuning of physical properties, as opposed to property modification via irreversible variation in microstructure of materials, is discussed in this article. The foremost example of external field-controlled electronic transport of a material is the “field effect transistors (FET).” However, the possibilities of tuning the macroscopic properties of materials with high charge carrier density have not been studied extensively. Large free carrier concentration in metals and high conducting oxides, however, can be of interest for specific applications. Despite the fact that the screening lengths of metals are extremely small, macroscopic property modulation can still be achieved via extremely small nanostructures (with very high surface-to-volume ratio). Moreover, electrochemical gating offers high surface charge density. While selected examples of tunable mechanical and magnetic properties of metals are cited, surface-charge-induced variation in electronic transport of metals (for both nanoporous and planar geometry) and high conducting transparent oxides are discussed in more detail.