Influence of the Voltage on Pore Diameter and Growth Rate of Thin Anodic Aluminium Oxide (AAO) Pattern on Silicon Substrate


By applying dual anodization procedures of aluminum (Al) thin film over silicon substrate under controlled anodizing process conditions, a thin anodic alumina (AAO) pattern with hexagonal honeycomb-like arrangement nano-pores and highly-regular aligned arrays was created. Anodizing DC voltage was thought to have an effect on pore size dimensions. With anodizing DC voltage, the pore diameter (30 - 110nm) showed a linear change. The rate of vertical growth of the nanopores was found to be proportional to the anodizing voltage. To achieve open-through pore nanostructure and ensure homogeneous electrochemical deposition of various nanostructures onto AAO pattern, a bottommost barrier layer of the AAO pattern was detached during dropping the DC voltage in the final period of the anodization process, followed by a pore widening wet treatment for numerous minutes at ambient temperature atmosphere. The features of the AAO pattern were inspected by using the field emission scanning microscope (FESEM) linked with an electron dispersive x-ray spectrometer (EDX) for chemical elements investigation.