New Design of ZnO Nanorod- and Nanowire-Based NO2 Room-Temperature Sensors Prepared by Hydrothermal Method

Abstract EN

Room-temperature gas sensors are attracting attention because of their low power consumption, safe operation, and long-term stability.

Herein, ZnO nanorods (NRs) and nanowires (NWs) were on-chip grown via a facile hydrothermal method and used for room-temperature NO2 gas sensor applications.

The ZnO NRs were obtained by a one-step hydrothermal process, whereas the NWs were obtained by a two-step hydrothermal process.

To obtain ZnO NW sensor, the length of NRs was controlled short enough so that none of the nanorod-nanorod junction was made.

Thereafter, the NWs were grown from the tips of no-contact NRs to form nanowire-nanowire junctions.

The gas-sensing characteristics of ZnO NRs and NWs were tested against NO2 gas at room temperature for comparison.

The gas-sensing characteristics of the sensors were also tested at different applied voltages to evaluate the effect of the self-activated gas-sensing performance.

Results show that the diameter of ZnO NRs and NWs is the dominant parameter of their NO2 gas-sensing performance at room temperature.

In addition, self-activation by local heating occurred for both sensors, but because the NWs were smaller and sparser than the NRs, local heating thus required a lower applied voltage with maximal response compared with the NRs.