Floating metal layer as top electrode over vertically aligned nanorod arrays using angle deposition technique

Abstract

A floating metal layer (FML) is realized over vertically aligned nanorod arrays (NRAs) using a newly developed angle deposition technique (ADT) that utilizes simultaneous metallization from two identical metal sources. The angle of the sources formed with the tip of the nanorod creates a shadow onto adjacent nanorods in the deposition direction. Computational estimation suggests the length of nanorods embedded in FML depends on the length of NRAs and separation distance between them, and normal height and lateral distance of sources from surface of the substrate. A layer of copper (Cu) is metalized using the proposed ADT on top of hydrothermally grown titanium dioxide NRAs (TiO2-NRAs) formed over fluorine-doped tin oxide (FTO) coated glass substrate (Cu/TiO2-NRA/FTO). Current–voltage characteristics through the resulting Cu/TiO2-NRA/FTO vertical device structure in macroscopically large area recorded by sweeping DC-voltage in cycles of exhibits resistive switching with transition from high to low resistance state during and regaining of the original high resistance state following negative differential resistance behavior during .