A solution flow system for hydrothermal-electrochemical growth of multilayered thin films

A solution flow system equipment for hydrothermal-electrochemical synthesis of advanced thin films has been designed, constructed, and successfully te sted. The synthesis using recyclable (aqueous) solutions as precursors can be carried out up to temperature of 200 degrees C and pressure of 50 kg cm( -2) utilizing electrochemical activation of the nucleation and growth proce sses. Any clear solution can be used as a precursor; there are almost no li mitations of the substrates used. The equipment is easy to use, versatile, and inexpensive. Applicability of the solution flow system for synthesis of advanced materials has been demonstrated using single-layer and multilayer BaTiO3-SrTiO3 thin films. Our equipment allows control of the microstructu re of the films in a nanometric scale by changing the preparation condition s, for example the growth rate can be increased by increasing the flow rate . In addition, the multilayered films can be prepared in only one experimen t just by changing the kind of flowing solution. The technique using the so lution flow under the hydrothermal-electrochemical conditions is an importa nt step in integration of the solution processing with the advanced device technology. (C) 1999 American Institute of Physics. [S0034-6748(99)01905-X] .