Electro-Physical Properties of Niobia Columnlike Nanostructures via the Anodizing of Al/Nb Layers

Abstract

Two types of niobia columnlike nanostructures were synthesized by anodization, reanodization, and chemical etching of sputter-deposited Al/Nb metal layers. The morphological properties of synthesized niobia columnlike nanostructures were determined by means of scanning electron microscopy. The electro-physical characteristics of niobia columnlike nanostructures were investigated in two measurement schemes. Aluminum layers of thickness 500 nm were used as contact pads. The current-voltage I-U characteristic has a nonlinear and nonsymmetrical character. The rising of temperature leads to an increase of the current. This behavior may indicate a p-n or metal-semiconductor junction. The initial resistance at 23 °C was 60 and 120 kOhms, the specific resistance to the height of the columns was 87 and 116 kOhms·nm−1, the calculated temperature coefficient of resistance appeared to be negative and rather low: $-1.39\times 10^{-2}$ and $-1.28\times 10^{-2}\mathrm{K}^{-1}$ for the niobia columnlike nanostructures reanodized at 300 and 450 V, respectively.