Sandeep K. Patil
Department of Materials Science and Engineering, University of Missouri--Rolla, Rolla, Missouri 65409
Nipun Shah
Materials Research Center, University of Missouri-Rolla, Rolla, Missouri 65409
Frank D. Blum
Materials Research Center and Department of Chemistry, University of Missouri-Rolla, Rolla, Missouri 65409
Mohamed N. Rahaman
Department of Materials Science and Engineering, University of Missouri-Rolla, Rolla, Missouri 65409
The concentration of hydroxyl (-OH) groups in epitaxial barium titanate (BaTiO3) films (thickness ≈ 200 nm), deposited on single-crystal strontium titanate (SrTiO3) at 150 °C by a hydrothermal technique, was investigated using x-ray photoelectron spectroscopy and Fourier transform infrared (FTIR) spectroscopy. After hydrothermal treatment, a broad FTIR resonance for the hydroxyl groups indicated a significant concentration of surface -OH groups in the films. The as-deposited films were subsequently treated hydrothermally with D2O, and the kinetics of the exchange reaction between -OH incorporated into the film and -OD from the D2O were studied using FTIR. For reactions carried out intermittently, the kinetics of the exchange reaction between -OH by -OD depended not only on the total reaction time, but also on the duration of each treatment. The broad FTIR hydroxyl resonance in the as-deposited hydrothermal film was significantly reduced only after heating for 1 h at 600-800 °C.