Biomedical Microdevices

, Volume 12, Issue 5, pp 849–854

Fluidic measurement of electric field sensitivity of Ti-GaAs Schottky junction gated field effect biosensors

  • Woo-Jin Chang
  • Ho-Jun Suk
  • A. K. M. Newaz
  • Kirk D. Wallace
  • Samuel A. Wickline
  • Stuart A. Solin
  • Rashid Bashir
Article

DOI: 10.1007/s10544-010-9439-9

Cite this article as:
Chang, W., Suk, H., Newaz, A.K.M. et al. Biomed Microdevices (2010) 12: 849. doi:10.1007/s10544-010-9439-9

Abstract

We report the electric field and pH sensitivity of fluid gated metal-semiconductor hybrid (MSH) Schottky structures consisting of a Titanium layer on n-type GaAs. Compared to standard field-effect sensors, the MSH Schottky structures are 21 times more sensitive to electric field of −46.6 V/cm and show about six times larger resistance change as pH of the solution is decreased from 8.17 to 5.54. The potential change at the fluidic gate and passivation layer interface by bias voltages and pH are mirrored by the metal shunt, resulting in larger depletion widths under the Schottky junction and resistance change as compared to sensors with no Schottky junction. 2D numerical simulation results are in good agreement with the measured data and suggest thinner mesa with lower doping density can further increase device sensitivity.

Keywords

Field effect biosensorSchottky junctionFluidic measurementElectric field sensing

Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  • Woo-Jin Chang
    • 1
  • Ho-Jun Suk
    • 1
  • A. K. M. Newaz
    • 2
    • 4
  • Kirk D. Wallace
    • 2
  • Samuel A. Wickline
    • 2
  • Stuart A. Solin
    • 2
    • 3
  • Rashid Bashir
    • 1
  1. 1.Department of Electrical and Computer Engineering, Department of Bioengineering, Micro and Nanotechnology LaboratoryUniversity of Illinois at Urbana-ChampaignUrbanaUSA
  2. 2.Department of Physics and Center for Materials InnovationWashington University in St. LouisSt. LouisUSA
  3. 3.Blackett LaboratoryImperial College LondonLondonUK
  4. 4.Department of Physics and AstronomyVanderbilt UniversityNashvilleUSA