Electronic conduction properties of indium tin oxide: single-particle and many-body transport

Abstract

Abstract.Indium tin oxide (Sn-doped In 2 O 3−δ or ITO) is an interesting and technologically important transparent conducting oxide. This class of material has been extensively investigated for decades, with research efforts focusing on the application aspects. The fundamental issues of the electronic conduction properties of ITO from 300 K down to low temperatures have rarely been addressed. Studies of the electricaltransport properties over a wide range of temperature are essential to unraveling the underlying electronic dynamics and microscopic electronic parameters. In this Topical Review, we show that one can learn rich physics in ITO material, including the semiclassical Boltzmann transport, the quantum-interference electron transport, and the electron-electron interaction effects in the presence of disorder and granularity. To reveal the avenues and opportunities that the ITO material provides for fundamental research, we demonstrate a variety of charge transport properties in different forms of ITO structures, including homogeneous polycrystalline films, homogeneous singlecrystalline nanowires, and inhomogeneous ultrathin films. We not only address new physics phenomena that arise in ITO but also illustrate the versatility of the stable ITO material forms for potential applications. We emphasize that, microscopically, the rich electronic conduction properties of ITO originate from the inherited freeelectron-like energy bandstructure and low-carrier concentration (as compared with that in typical metals) characteristics of this class of material. Furthermore, a low carrier concentration leads to slow electron-phonon relaxation, which causes (i) a small residual resistance ratio, (ii) a linear electron diffusion thermoelectric power in a wide temperature range 1-300 K, and (iii) a weak electron dephasing rate. We focus our discussion on the metallic-like ITO material.

Tuning Nanocrystal Surface Depletion by Controlling Dopant Distribution as a Route Toward Enhanced Film Conductivity

“…Conduction of this type has been observed in granular ITO thin films and is ascribed to a granular metal conduction mechanism. [36][37][38] We note that while hopping conduction is a description of electrons overcoming a Coulombic blockage by undergoing hops of temporally varying distances, the granular metal conduction model describes the competition between Coulombic barriers and NC-NC coupling. Granular metal conduction depends on the grain (NC) size and the degree of coupling, reflected in tunneling conductance between neighboring NCs, rather than the electron localization length.…”

Effects of Al Doping on the Properties of ZnO Thin Films Deposited by Atomic Layer Deposition

“…There are various TCO materials, including In, Sb, Zn, Cd, Sn metal oxides, and their composite oxides. Among them, indium tin oxide (ITO) film is the most widely used TCO material [ 5 ]. However, the scarce and toxic nature of indium and instability of ITO are the main obstacles for its further development, which arouses the interests of researchers to explore alternative TCO materials for ITO.…”

Weak localization and size effects in thin In 2 O 3 films prepared by autowave oxidation

“…This is because indium oxide films are the most demanded among the TCO. In particular, at low temperatures, information about the electrical and magnetoresistive properties of indium oxide can give additional insight on quantum transport in lowdimensional systems [10]. At high temperatures, comparable to room temperature, nonlinear optical properties of indium tin oxide films can be used to create devices for nanophotonics, plasmonics, and nonlinear nano-optics [11].…”

“…The presence of negative magnetoresistance can be caused by a variety of quantum electronic effects [10]. Recently, the negative magnetoresistance has been observed at low temperatures for pure and doped TCO films.…”