Gas sensing properties of p-type hollow NiO hemispheres prepared by polymeric colloidal templating method

Abstract

This work presents a simple and versatile route to produce macroporous p-type metal oxide thin films. Two-dimensional arrays of p-type NiO films with a hollow hemisphere structure were fabricated by colloidal templating and RF-sputtering followed by a subsequent heat treatment. The diameter and shell thickness of the NiO hemisphere were 800 nm and 20 nm, respectively. X-ray diffraction and high-resolution transmission electron microscopy analysis indicate that the pure NiO phase with grain size of 10 nm was obtained at calcination temperatures that exceeded 450 degrees C. Close-packed arrays of hollow NiO hemispheres were found to exhibit p-type gas sensing properties against (CO, H(2), C(3)H(8), CH(4), NO(2), and C(2)H(5)OH), leading to significantly enhanced responses to C(2)H(5)OH (R(gas)/R(air) = 5.0 at 200 ppm). (C) 2010 Elsevier B.V. All rights reserved.