Thermopower for anatase epitaxial films (: ) and the gate voltage dependence of for thin film transistors (TFTs) based on films were investigated to clarify the electronic density of states around the conduction band bottom. The slope of the plots was , which is an order magnitude smaller than that of semiconductors , and the values for the TFTs increased with in the low region, suggesting that the extra tail states are hybridized with the original conduction band bottom.
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