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

doi:10.1007/s10544-010-9439-9

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

Research output: Contribution to journal › Article › peer-review

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 p^H 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.

Original language	English (US)
Pages (from-to)	849-854
Number of pages	6
Journal	Biomedical microdevices
Volume	12
Issue number	5
DOIs	https://doi.org/10.1007/s10544-010-9439-9
State	Published - Oct 2010

Keywords

Electric field sensing
Field effect biosensor
Fluidic measurement
Schottky junction

ASJC Scopus subject areas

Biomedical Engineering
Molecular Biology

Online availability

10.1007/s10544-010-9439-9

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title = "Fluidic measurement of electric field sensitivity of Ti-GaAs Schottky junction gated field effect biosensors",

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 = "Electric field sensing, Field effect biosensor, Fluidic measurement, Schottky junction",

author = "Chang, {Woo Jin} and Suk, {Ho Jun} and Newaz, {A. K M} and Wallace, {Kirk D.} and Wickline, {Samuel A.} and Solin, {Stuart A.} and Rashid Bashir",

note = "Funding Information: Acknowledgements This work was supported by the U.S. NIH under Grant 1U54CA11934201. S.A.S. also received support from the U.S. NSF under Grant ECCS-0725538. S. A. S., S. A. W., and K. D. W. are cofounders of and have a financial interest in PixelEXX, Inc. a start-up company whose mission is to market imaging arrays. W.J.C. was partially supported from the ERC for Advanced Bioseparation Technology, KOSEF, Korea. Two of the authors (W.J.C. and H.J.S.) contributed equally to this work.",

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doi = "10.1007/s10544-010-9439-9",

language = "English (US)",

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journal = "Biomedical microdevices",

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T1 - Fluidic measurement of electric field sensitivity of Ti-GaAs Schottky junction gated field effect biosensors

AU - Chang, Woo Jin

AU - Suk, Ho Jun

AU - Newaz, A. K M

AU - Wallace, Kirk D.

AU - Wickline, Samuel A.

AU - Solin, Stuart A.

AU - Bashir, Rashid

N1 - Funding Information: Acknowledgements This work was supported by the U.S. NIH under Grant 1U54CA11934201. S.A.S. also received support from the U.S. NSF under Grant ECCS-0725538. S. A. S., S. A. W., and K. D. W. are cofounders of and have a financial interest in PixelEXX, Inc. a start-up company whose mission is to market imaging arrays. W.J.C. was partially supported from the ERC for Advanced Bioseparation Technology, KOSEF, Korea. Two of the authors (W.J.C. and H.J.S.) contributed equally to this work.

PY - 2010/10

Y1 - 2010/10

N2 - 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.

AB - 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.

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KW - Field effect biosensor

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KW - Schottky junction

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

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