Mechanisms of composite-hydroxide-mediated approach for the synthesis of functional ZnO nanostructures and morphological dependent optical emissions Mechanisms of composite-hydroxide-mediated approach for the synthesis of functional ZnO nanostructures and morphological dependent optical emissions
1National Institute of Lasers and Optronics (NILOP), P.O. Nilore 45650, Islamabad, Pakistan
2Trinity College Dublin, School of Physics, Dublin 2, Ireland
3Department of Mechanical Engineering, Muhammad Ali Jinnah University, Islamabad, Pakistan
Adv. Mater. Lett., 2015, 6 (7), pp 592-599
Publication Date (Web): Jul 12, 2015
Copyright © IAAM-VBRI Press
We report synthesis of the functional ZnO nanostructures (nanowires, nanorods) by a cost-effective and efficient method; called composite-hydroxide-mediated (CHM) approach. Effect of the processing temperature on the particle size, morphology, and subsequently morphological dependent optical emissions is investigated. Needle-shaped nanowires are obtained at 200 and 220oC, of about (500-1500) nm in length, while at 250oC; nanorods are formed with length in the range of (200-460) nm and width (10-30) nm. Optical study reveals that ZnO nanorods show only ultra-violet (UV) emission while bent nanowires demonstrate both UV and green emissions simultaneously. The week green emission at 2.4 eV indicates no efficient trapping of the photo-generated hole in the nanostructures. Phase purity, crystalline structure, size and chemical nature of the product are probed by XRD, EDX, Raman spectroscopy and FT-IR. The particle size estimated from the spatial correlation phonon confinement model for the E2 (high) phonon mode. The applied approach is believed to be efficient, and a direct route for the synthesis of a wide range of simple and complex oxide nanostructures for novel electro-optical nanodevices.
SEM, nanorods and nanowires, Raman spectroscopy, optical properties, morphology dependent emissions.