Controllability study on the preparation of pure phase BiFeO_3 thin films by liquid phase self-assembled method

摘要

Pure phase BiFeCh (BFO) thin films were prepared on the ITO/glass substrates covered with function-alized OTS self-assembled monolayers (SAMs) by controllable liquid phase self-assembled method. The hydrophobic surface of OTS-SAMs was changed into hydrophilic surface after UV irradiation, which is helpful to make BFO precursor solutions fully wet the substrate surface. A dense film was formed only on the hydrophilic silnaol group regions, which shows the selectively deposition of BFO precursors. Changing the pH value of BFO precursor solutions will affect the phase purity. The pure phase BFO thin films can be obtained under various pH values, which indicates that the liquid phase self-assembled method is controllable. All pure phase BFO films are dense, smooth, well-grown polycrystalline films, but the size of grains increased gradually along with the increase of pH values. The micropattern of BiFeO_3 film has clear edges. The possible growth mechanism of BFO thin films was discussed.