A micro sensor based on TiO2 nanorod arrays for the detection of oxygen at room temperature

A new micro gas sensor based on the TiO2 nanorod arrays (NRAs) was developed and its response properties to oxygen (O2) at room temperature were investigated. The micro sensor combined a pair of micro interdigitated electrodes realized by the MEMS process and sensing materials based on the TiO2 NRAs. The TiO2 NRAs were selectively grown on the patterned straps of Ti/Pd films through the acid vapor oxidation (AVO) process. Relationship between the morphology of the TiO2 NRAs and reaction temperatures was analyzed with the scanning electronic microscopy (SEM) and X-ray diffraction (XRD). The results indicate that the diameters of the TiO2 NRs enlarged as the reaction temperature increased from 140 °C to 180 °C. The TiO2 NRAs sensors showed a good response to O2 at room temperature (25 °C) due to the large specific surface areas of the TiO2 NRs and the TiO2 NR/NR junctions. The TiO2 NRAs sensors prepared at 140 °C for 3 h exhibited better response properties to O2 at room temperature with a fast response and recovery time. The research indicates that the TiO2 NRAs prepared by the simple AVO process is a good choice for detecting O2 at room temperature.