[摘要]：Uniform SnO(2) nanorod arrays have been deposited at low temperature by plasma-enhanced chemical vapor deposition (PECVD). ZnO surface modification is used to improve the selectivity of the SnO(2) nanorod sensor to H(2) gas. The ZnO-modified SnO(2) nanorod sensor shows a normal n-type response to 100 ppm CO, NH(3), and CH(4) reducing gas whereas it exhibits concentration-dependent n-p-n transitions for its sensing response to H(2) gas. This abnormal sensing behavior can be explained by the formation of n-ZnO/p-Zn-O-Sn/n-SnO(2) heterojunction structures. The gas sensors can be used in highly selective H(2) sensing and this study also opens up a general approach for tailoring the selectivity of gas sensors by surface modification.
