Optical properties of octahedral KTaO3 nanocrystalline

Potassium tantalite (KTaO3) nanocrystalline with octahedral morphologies were synthesized by hydrothermal route. The as-prepared samples have pyrochlore structures, which are consisted of a large quantity of octahedral nanocrystalline with a uniform edge size of about 500 nm. The band gap energy for KTaO3 nanocrystalline is about 4.06 eV. The Raman studies show that the vibration modes of nanocrystalline are red-shifted and broadened, which are due to defects of KTaO3 nanocrystalline and weak quantum confinement effect. PL study exhibits that a broad blue light emission band peaking at about 490 nm (2.53 eV) was observed at room temperature. Oxygen vacancies should be accounted for this emission peak.