Study on sputtered a-Si:H for micro optical diffusion sensor using laser-induced dielectrophoresis

Makoto Kamata, Kan Yamada, Yoshihiro Taguchi, Yuji Nagasaka

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)


In this study, a MEMS sensing device, which is applicable to point-of-care testing (POCT), is developed by integrating an optical manipulation and detection technique. The diffusion coefficient is a parameter, which is sensitive to the size, the construction and the interaction of the sample, thus, the measurement of the diffusion coefficient of the bio-sample, such as proteins, is useful for the clinical diagnosis to detect interactions and conformational changes with high sensitivity. Several diffusion sensing methods have been developed, however, the technique applicable to POCT is not established because of the difficulties due to the requirement of the measurement in a short time and a small sensing device. In this study, in order to realize a high-speed detection (ms ∼ s) with small sample volume (∼ μl) and small apparatus (tens of cm) without particular preparations, the micro optical diffusion sensor utilizing laser-induced dielectrophoresis (LIDEP), which is a manipulation technique based on optoelectronic tweezers, is developed. The microscale concentration distribution is formed in the microchannel by LIDEP and act as the transient diffraction grating, then, the diffusion phenomenon is optically observed. For these techniques, a photoconductive layer is essential and a hydrogenated amorphous silicon (a-Si:H) deposited by a plasma-enhanced chemical vapor deposition is generally utilized as the layer. In this study, the a-Si:H is deposited using a reactive RF magnetron sputtering method under several conditions, while changing the source gas compositions. The sensing device is fabricated with proposed a-Si:H, and the feasibility study for bio-sample measurement is conducted.

Original languageEnglish
Title of host publicationMOEMS and Miniaturized Systems XV
EditorsWibool Piyawattanametha, Yong-Hwa Park
ISBN (Electronic)9781628419955
Publication statusPublished - 2016
EventMOEMS and Miniaturized Systems XV - San Francisco, United States
Duration: 2016 Feb 152016 Feb 17

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherMOEMS and Miniaturized Systems XV
Country/TerritoryUnited States
CitySan Francisco


  • Diffusion coefficient
  • Hydrogenated amorphous silicon
  • Laser-induced dielectrophoresis
  • Reactive RF magnetron sputtering
  • Sensing chip

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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