Highly sensitive MEMS-type micro sensor for hydrogen gas detection by modifying the surface morphology of Pd catalytic metal

Jung Sik Kim, Bum Joon Kim

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Abstract

In this study, highly sensitive hydrogen micro gas sensors of the multi-layer and micro-heater type were designed and fabricated using the micro electro mechanical system (MEMS) process and palladium catalytic metal. The dimensions of the fabricated hydrogen gas sensor were about 5 mm × 4 mm and the sensing layer of palladium metal was deposited in the middle of the device. The sensing palladium films were modified to be nano-honeycomb and nano-hemisphere structures using an anodic aluminum oxide (AAO) template and nano-sized polystyrene beads, respectively. The sensitivities (Rs), which are the ratio of the relative resistance were significantly improved and reached levels of 0.783% and 1.045 % with 2,000 ppm H2 at 70 °C for nano-honeycomb and nano-hemisphere structured Pd films, respectively, on the other hand, the sensitivity was 0.638% for the plain Pd thin film. The improvement of sensitivities for the nano-honeycomb and nano-hemisphere structured Pd films with respect to the plain Pd-thin film was thought to be due to the nanoporous surface topographies of AAO and nano-sized polystyrene beads.

Original languageKorean
Pages (from-to)532-537
Number of pages6
JournalKorean Journal of Materials Research
Volume24
Issue number10
DOIs
StatePublished - 2014

Keywords

  • Hydrogen sensor
  • MEMS
  • Nanoporous film
  • Palladium
  • Sensitivity

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