Ambient effects on electric-field-induced local charge modification of TiO 2

Abstract

We investigated the surface potential of TiO 2 single crystals using scanning probe microscopy (SPM) under different gas environment. The SPM tip-induced electrical stress resulted in reversal in the surface potential, V surf, polarity only in H 2/Ar (ΔV surf 0.30 eV) and not in Ar and O 2. Quantitative measurement of the influence of ambient gas on the surface potential led us to develop a model where the adsorbed oxygen molecules and oxygen vacancies interact to change their relative concentration leading to different surface potential in TiO 2. These results will give us insights into ambient-dependent physical phenomena in oxide thin film nanostructures. © 2012 American Institute of Physics.