Abstract

The hydrothermal preparation of perovskite thin films of ABO3 type is described in this article. The hydrothermal and the hydrothermal-electrochemical methods, the materials which can be synthesized in thin films, as well as the state of the art of their applications are presented and discussed. The hydrothermal process consists of the chemical reaction between a metallic substrate and alkali-earth ions in solutions at temperatures above 100 °C and at pressures above atmospheric. This technique presents several advantages: allows thin film preparation of perovskites at temperatures below 200 °C; it is possible to coat non-metallic substrates such as plastics, glass and silicon, if these have the appropriate metallic coating; and the films are polycrystaline and adherent. This paper describes the electrical properties of BaTiO3 films on silicon, as well as their applications as sensors and actuators. Finally the possibilities and limitations of the hydrothermal method and its perspectives are discussed.