Our results show that growth of horizontal ZnO nanowires on sapphire a-plane takes place epitaxially with misfit dislocations much fewer than theoretically expected. In highly lattice mismatched systems, misfit dislocation formation is the common route for overlayer strain energy relaxation. We attribute formation of fewer dislocations to partial zinc oxide strain relaxation to sapphire surface. This is concluded from the observation of sapphire a-plane bending and propagation of an elastic deformation as a nanowire grows with a significant rate of 20 nm/S. A critical nanowire thickness is defined beyond which misfit energy largely relaxes to dislocations, changing the horizontal growth mode to standing one.
Citation: Journal of the American Chemical Society
Pub Type: Journals