Sensitivity enhancement of lateral zinc oxide nanowire gas sensors

A novel method for the fabrication of lateral zinc oxide (ZnO) nanowires bridging architecture was proposed. ZnO nanowires with a length greater than the electrode spacing were bridged between the interdigital electrodes. It is noteworthy that the lateral bridging architecture sensor has more enhanced sensitivity characteristics than the vertical-type sensor. For example, at the optimum operating temperature of 300 degree celsius, the lateral ZnO nanowire gas sensor has a response of 6.5 for 20 ppm acetone (C3H6O), which is more than twice that of the vertical nanowire gas sensor (2.6). The lateral gas sensor designed in this paper has great advantages in response time and recovery time. Furthermore, the enhanced sensing mechanisms were comprehensively discussed. The gas sensing performance of the lateral-type sensor is improved because the current is transported along the nanowire rather than along the bottom layer of the substrate. This lateral sensor provides an attractive approach for the development of new structured gas sensors with high sensitivity and high integration.