Study On Solid - State Nanostructures Based On Anodized Aluminum Template On Silicon

With the widespread using of coal, oil, natural gas and other traditional energy sources, the global energy and environmental issues become increasingly prominent. The effective conversion and utilization of new energy has become the focus issue of the industry and scientific research. The potential advantages of both high energy density and high power density make nano-templates-based solid nano-capacitors become a very promising energy storage element compared to conventional batteries and Electrochemical Supercapacitors. In this thesis, three dimensional nanocapacitor arrays based on the AAO template on Si substrate acts as the basic steering idea. The fabrication process of the AAO template on Si substrate is studied firstly, and then by using the AAO template combined with atomic layer deposition (ALD) technology, the nano-solid capacitor arrays are formed on the AAO/Si substrate. Specifically it includes the following aspects:(1) First, the effects of aluminum film deposition method (magnetron sputtering, thermal evaporation) on the AAO template of one step anodization are analyzed. Porous alumina depth of about580nm is obtained when the oxidation time is5min, and the oxidation rate is about1.9nm/s. Then, by pore widening of the AAO template in5wt%phosphoric acid solution, the effects of pore widening time on the the nanopores characteristics are also studied. The result shows that the size of nanopore grows with the increasing of the pore widening time when the time is less than60min. The pore characteristics achieve the best in60min and the pore is damaged when the pore windening time is to further extend, ultimately forming the alumina nanowires. In addition, with the increasing of the oxidation time, the self-organized growth process of nanopores is more fully, and the shape of nanopore in the AAO template becomes more regular.(2) By using the twice oxidization AAO template on Si substrate, the effects of different oxidation time and pore widening time on the pore characteristics are also discussed. Experiment result shows that the nanopores reach the best when the pore widening time is1min in5wt%phosphoric acid solution. Meanwhile, based on the stratification of the deposited aluminum film or voltage fluctuations principle, the inconsistent in the top and bottom of nanopore in the experimental procedure is also explained. In addition, it is also found that the adhesion of AAO template and the Si substrate could be improved when the aluminum film is treated in N2atmosphere at500℃by rapid thermal treatment. Finally, using the ALD method, the aspect 600nm/70nm hole is filled with ZnO film, revealing a good completely filling effects.(3) Using the AAO/Si template and ALD technology, the nano-capacitor arrays based on AZO/Al2O3/AZO (12nm/10nm/12nm) structure are fabricated, showing high capacitance density of15.3fF/μm. The RC time constant of the nano-capacitor arrays is300ns, showing good power characteristics of the electrostatic capacitance. By charging the capacitor at different voltage, it is found that the charging process has no relation with the voltage supply, which is in consistent with the electrostatic capacitor charge and discharge theory.