Abstract

We have investigated the time dependence of water adsorption on polycrystalline barium titanate films fabricated on silicon under hydrothermal conditions. X-ray photoelectron spectroscopy showed surface OH groups on the films but no molecular H2O. The time dependent behavior of water adsorption was investigated by measuring the work function changes with a Kelvin probe. The film response time for both increasing and decreasing humidity is less than one minute. The typical amplitude change was about 0.05 eV for a 50% humidity variation, with higher variations at lower humidity.