Study of Morphological and Related Properties of Aligned Zinc Oxide Nanorods Grown by Vapor Phase Transport on Chemical Bath Deposited Buffer Layers

Abstract

c -axis aligned ZnO nanorods were deposited by vapor phase transport on textured chemical bath deposited buffer layers. In this work, we examine the role of the buffer layer and how it influences the vapor phase transport deposition process using both scanning and transmission electron microscopes and related techniques. Vapor phase transport deposition on chemical bath deposited buffer layers is a complex growth process with many simultaneously occurring effects including (i) substantial morphological transformation at high temperature, which influences the base of the nanorods; (ii) the formation of a mixed amorphous/crystalline Zn x Si 1– x O y interface during the vapor phase transport growth on silicon substrates; (iii) the overgrowth of the ZnO seed layers by the silica interface rendering them inactive for nanorod nucleation, suggesting there is a minimum critical thickness ZnO buffer layer necessary for vapor phase transport growth of ZnO nanorods on silicon substrates. We discuss the relative importance of these effects on the overall growth process and use this understanding to explain previous results in the literature.