title: Hydrogen sensing properties of dielectrophoretically assembled SnO2 nanoparticles on CMOS-compatible micro-hotplates.
abstract: We fabricated nanoparticle-based gas through in situ ac dielectrophoretical assembling of drop-coated SnO(2) nanoparticles to bridge the gap between electrodes with high aspect ratio. While the conventional dielectrophoresis (DEP) adopts a microfluidic system for continuous flow of the solution during the process, we just drop-coated a small amount of solution onto the electrodes and executed in situ DEP for a very short time. This is a very simple, cost-effective, time-saving, and highly reproducible process. We fixed the duration time and applied voltage for the DEP at 1 s and 1 V respectively and changed the frequencies from 1 up to 500 kHz. I-V characteristics of the samples were checked and it was found that DEP samples fabricated at 1 s, 1 V and 150 kHz conditions showed considerably higher connectivity of the nanoparticles. This can be attributed to the excellent step coverage achieved by ac DEP under those conditions. The devices drop-coated and dielectrophoretically assembled at other ac frequency conditions showed poor connectivity. Hydrogen gas sensing properties of the sensors fabricated under 1 s, 1 V and 150 kHz conditions were checked by flowing through 160 ppm H(2). The sensitivity reaches a maximum value of ~ 700% at 350 °C. The response time is ~ 200 s at 350 °C.
authors: Department of Electronic and Electrical Engineering, and Sungkyunkwan University Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
authors: Youngreal
authors: Y
authors: Kwak
authors: Jianwei
authors: J
authors: Wang
authors: Sunglyul
authors: S
authors: Meang
authors: Gil-Ho
authors: GH
authors: Kim