Defects on the Surface of Ti-Doped MgAlO Nanophosphor.

Ti-doped nano MgAlO for white emission was synthesized by combustion method. Extrinsic Schottky defects, Al vacancies and Ti dopant in Al sites, which are considered to be responsible for bluish-white emission, were observed by STEM on the surface of Ti-doped nano MgAlO powder. The stabilities of the Schottky defect associates, (Ti-V''')'', were demonstrated by DFT calculation.

Enhancement of UV emission in ZnO nanorods by growing additional ZnO layers on the surface.

Ultraviolet (UV) photoluminescence emission from ZnO nanorod arrays was greatly enhanced by growing additional thin ZnO layers on the surface after thermal reduction of the nanorods. Appropriate selection of additives based on the shape of the original ZnO samples was found to be an important factor in designing the solution composition for growing the additional ZnO layers. This is because the additives modify the growth rates with respect to crystallographic planes.

Calculation of formation energy of oxygen vacancy in ZnO based on photoluminescence measurements.

The formation energy of an oxygen vacancy in ZnO was calculated. The photoluminescence intensity of green emission was used as a measure of vacancy concentration, and its variation as a function of reduction temperature was monitored. This enabled a thermodynamic approach based on experimental data, which is in contrast with most previous studies, which focused on a theoretical treatment based on first principles methods.