Influence of annealing temperature on the band structure of sol-gel Ba0.65Sr0.35TiO3 thin films on n-type Si(100)

The annealing temperature effect on the band structure of Ba0.65Sr0.35TiO3 (BST) thin films coated on n-type Si(100) substrate was investigated by ellipsometry and x-ray photoelectron spectroscopy. The band energy shifts of sol-gel BST films annealed at different temperatures are dependent on their developed microstructure. Related to the amorphous BST films annealed at 600°C, the polycrystalline BST film annealed at 700°C exhibits narrow band gap, upwards-moved Fermi level, and downwards-moved conduction band minimum, which are believed to contribute the enhanced field emission of BST-coated Si field emitter arrays.