液晶鋳型-水熱処理法による低次元量子閉じ込め構造酸化物半導体の合成と光物性

Oxide semiconductors with MCM-50--like layered structures are synthesized by liquid crystal templating followed by hydrothermal treatment. The band gap energy of hydrothermal-treated lamellar TiO$_2$ shows a substantial blue shift of $Delta E_g=0.31$~eV. The thickness of the 2-dimensional TiO$_2$ sheets estimated from $Delta E_g$ by using Blus' equation describing the quantum-confinement effect agrees within a factor of 1.5 with that determined from TEM observation. A new photoluminescence peak appears at $ca.$ 380~nm, being in good accordance with the wider band gap energy of the lamellar TiO$_2$. Lamellar Fe$_2$O$_3$ and Bi$_2$O$_3$ show sharp absorption peaks at the lower energy of the absorption edges, suggesting exciton absorption observable at root temperature.