Fluctuation-Induced Tunneling Conductivity in Nanoporous TiO2 Thin Films

The electronic mechanisms responsible for dark conductivity in nanoporous TiO2 thin films remain only partially understood, although they control the efficiency of charge transport in a wide range of technological applications. Measurements in the 78–335 K temperature range show DC conductivity valu...

Full description

Saved in:
Bibliographic Details
Published in:The journal of physical chemistry letters 2011-08, Vol.2 (15), p.1931-1936
Main Authors: Konezny, Steven J, Richter, Christiaan, Snoeberger, Robert C, Parent, Alexander R, Brudvig, Gary W, Schmuttenmaer, Charles A, Batista, Victor S
Format: Article
Language:English
Subjects:
Electron Transport, Optical and Electronic Devices, Hard Matter
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The electronic mechanisms responsible for dark conductivity in nanoporous TiO2 thin films remain only partially understood, although they control the efficiency of charge transport in a wide range of technological applications. Measurements in the 78–335 K temperature range show DC conductivity values spanning over 4 orders of magnitude, with a high-temperature Arrhenius dependence that gradually changes into a temperature-independent plateau at low temperatures. We show evidence that a fluctuation-induced tunneling conductivity (FITC) mechanism is fully consistent with the experimental data. Quantitative agreement is demonstrated for the entire temperature range (T = 78–335 K) with a FITC model parametrized according to atomistic models of nanoporous TiO2 and the characterization of the films by X-ray diffraction and scanning electron microscopy measurements. These findings suggest that dark DC conductivity in nanoporous TiO2 films depends strongly on the properties of the junctions linking the constituent nanoparticles.
ISSN:1948-7185
1948-7185
DOI:10.1021/jz200853v