| AVS 58th Annual International Symposium and Exhibition | |
| MEMS and NEMS Group | Friday Sessions |
| Session MN-FrM |
| Session: | Characterization of Materials and Structures at the Micro- and Nano-scale |
| Presenter: | Chao-Hung Chou, National Taiwan University |
| Authors: | C.H. Chou, National Taiwan University C.H. Chen, National Taiwan University W.-C. Tian, National Taiwan University T.H. Chan, National Taiwan Normal University C.-J. Lu, National Taiwan Normal University |
| Correspondent: | Click to Email |
The purpose of this study is to develop a sensitive gas sensor with engineered TiO2 nanostructures using semiconductor nanotechnologies for micro gas chromatography. Many TiO2 nanowires for gas sensing nowadays were fabricated by chemical synthesis methods, and the nanowire arrays are in irregular formats and the amount of sensing material may be varied chip to chip. The behavior of sensing repeatability of these TiO2 nanowires using conventional methods is hard to control.
With the combination of E-beam lithography and the TiO2 thin film deposition, the TiO2 sensing nanowire arrays with well-controlled structures (100-300 nm wide with 1 μm period ), were placed in between the Au interdigitated electrodes. A microheater were fabricated by deposition of the 3/50 nm thick Cr/Au films on the backside of the sensor. The great linear heating with increasing input power and uniform heating (329.3 ℃ in average, STDV of 9.3 ℃, power of ~0.8 W) were obtained through an IR camera.
The performance of nanowire detector (100 nm wide, 183.5 MΩ) is compared to the microwire detector (20 μm wide, 24.6 MΩ) at various ethanol and benzene concentrations or at various operation temperatures. The measured resistance to the initial resistance ratio of the nanowire detector changed from 1 to 0.35 at 284 ℃ at 6.5% ethanol concentration. The effects of the rapid thermal annealing and an O2 plasma treatment to improve the sensor performances is investigated and will be presented.