One Step Synthesis of Pure Cubic and Monoclinic HfO_2 Nanoparticles: Effects of Temperature and Ambient on the Photoluminescent Properties

摘要

We report on the one-pot synthesis and characterization of pure cubic and monoclinic phase HfO_2 nanoparticles. An average particles size of 2.6 nm was estimated from transmission electron microscopy studies. The equivalent synthesis conditions of the two polymorphs provided means for direct comparison of their optical absorption and emission properties, which are found to exhibit different behaviors as functions of temperature and ambient. The origin of the strong visible luminescence observed from both cubic and monoclinic HfO_2 is discussed in terms of surface-defects and nanosize of the particles. The comparative analysis of the PL responses of the two polymorphs suggests that emission at 3.1eV originates from the oxygen vacancy related defects.