Plasma Surface Modification and Gas Sensing Properties of SnO2 Thin Films Prepared by Plasma Enhanced Chemical Vapor Deposition

Abstract

SnO2 thin films were deposited by RF inductively coupled plasma enhanced chemical vapor deposition (PECVD) using dibutyltin diacetate as the precursor. The as-deposited SnO2 thin films were granular with a grain size of 20 nm. The as-deposited thin films were post-treated in the plasma to modify the films surface morphologies. After plasma treatment, uniform nanorods in the size of Phi7 times 200 nm were observed in the plasma-treated SnO2 thin films. The gas sensing properties of the as-deposited and plasma-treated SnO2 thin films were comparatively studied. The plasma-treated sample with nanorods showed much higher sensitivity, faster response and shorter recovery time compared to the as-deposited sample with nanograins. The tremendous improvement of the gas sensing properties of the plasma-treated sample was believed to be attributed to the intrinsically small grain size comparable to the space-charge length and high surface-to-volume ratios associated with the nanorods