Synthesis and Characterization of TiO2 Micro- and Nano-Structures with Variable Morphology and Aluminum Content

Achieving a high surface to volume ratio is of advantage in many applications of semiconducting oxides, which can be obtained by reducing the size of the material toward the nanoscale. Beside size reduction, morphology variability and doping content could also induce differences in the luminescence of structures in the micro- and nano-scale widening their applicability. Elongated rutile TiO2 nano- and micro-structures are fabricated by an evaporation-deposition method using TiN as precursor at temperatures ranging from 800 to 900 degrees C. Aluminum doped TiO2 micro- and nano-structures are also grown at 940 degrees C. The presence of Al hinders the growth of structures and retards the anatase to rutile transition. The as-grown low dimensional structures are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, and cathodoluminescence (CL). The luminescence of the samples depends on the size, morphology, and aluminum content and is mainly dominated by an emission at 1.52eV and weaker emissions at 2.45 and 2.9eV, the origin of which is discussed in this work.