The effect of different oxide layers on the sensing properties of anodic alumina nanoporous film

Abstract

In the present work, anodized aluminum oxide template was prepared by accelerated mild anodization technique in 0.6M phosphoric aside and 175 V,anodization voltage. Pore widening was performed by chemical etching in 0.5M phosphoric aside for 8, 16, 32, 40 minutes. Scanning Electron Microscopy (SEM) images showed the pores diameter exponentially increases with etching time. By deposition silver contacts on the prepared samples setting a RC circuit, applying impedance spectroscopy, the characteristics of the humidity sensor based on constructed samples were investigated. The maximum response was seen for the sample etched at 40 minutes. For this sample, the detectable threshold of relative moisture was 30% and the response and the recovery time were 8, 2 second respectively.