Effect of Hydrogen on the Dielectric and Photoelectrochemical Properties of Sputtered TiO2 Films

Publisher Website
Google Scholar
Abstract
The electrochemical and photoelectrochemical properties of sputtered films of thick, have been investigated using a variety of electrometric techniques, for films sputtered on cooled substrates in both pure oxygen and oxygen/argon mixtures. Good photoresponse was achieved only for films sputtered in pure oxygen and then only after a cathodic electrochemical treatment that results in a 10‐fold increase in photocurrent, but no change in the potential for photocurrent onset. Evidence exists for three modes of electrochemical incorporation of hydrogen in the films: (i) irreversible filling with hydrogen which becomes bound to the lattice and is probably responsible for the 10‐fold increase in photocurrent through trap‐filling mechanism; (ii) filling to the extent of one per 3.7Ti with hydrogen that can be removed at anodic potentials only when the film is under illumination. This hydrogen does not act as electron donor in the dark, but leads to a large increase in the dielectric constant of the film; and (iii) reversible filling with hydrogen under potential control. Interpretation of Mott‐Schottky plots is complicated by one or more of hydrogen incorporation, hydrogen adsorption, and dielectric saturation processes. However, the doping density is determined to be ≤1017 cm−3.

This publication has 0 references indexed in Scilit: