Analysis of arrayed nanocapacitor formed on nanorods by flow-rate interruption atomic layer deposition

Flow-rate interruption (FRI) atomic layer deposition (ALD) technique was adopted to fabricate AZO/Al ₂ O ₃ /AZO thin film on a ZnO nanorod array template at low temperature. The high quality amorphous dielectric Al ₂ O ₃ layer was deposited at 50 °C. The template with an average of 0.73 μm in length was made by a simple hydrothermal method on a c−plane sapphire with an AZO seed layer. Using Polystyrene (PS) microspheres were served as a mask to form vertical and well-aligned ZnO nanostructures. Field-emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) images show ALD to have achieved good step coverage and thickness control in the thin films structure coating. The capacitance density of the arrayed template nanocapacitor increased more than 100% than those of the thin film capacitor at an applied frequency of 10 kHz. These results suggest that the ZnO-arrayed template could enhance energy storage capability by providing significant surface area. This structure provides a concept for high surface-area nanocapacitor applications.