The effect of residual stresses in the ZnO buffer layer on the density of a ZnO nanowirearray

Abstract

Density control is a valuable concern in the research of ZnO nanowire arrays. In this study,unannealed and annealed ZnO thin films were used as substrates to fabricate ZnO nanowirearrays. In the unannealed thin film, an inhomogeneous distribution of the nanowire arraywas found: the density of nanowires decreases with the increase of distance to theedge. In the annealed thin film, the density of nanowire array becomes largerand more homogeneous. Moreover, nanowires are found in high density alongmicrocracks. It is proposed that the residual stresses in the thin film and the density ofthe nanowire array are in inverse proportion, leading to the results mentionedabove. The relationship between residual stresses and the density of nanowires willhave potential applications in modifying the density of ZnO nanowire arrays.