title: Electrostatic Limit of Detection of Nanowire-Based Sensors.
abstract: Scanning gate microscopy is used to determine the electrostatic limit of detection (LOD) of a nanowire (NW) based chemical sensor with a precision of sub-elementary charge. The presented method is validated with an electrostatically formed NW whose active area and shape are tunable by biasing a multiple gate field-effect transistor (FET). By using the tip of an atomic force microscope (AFM) as a local top gate, the field effect of adsorbed molecules is emulated. The tip induced charge is quantified with an analytical electrostatic model and it is shown that the NW sensor is sensitive to about an elementary charge and that the measurements with the AFM tip are in agreement with sensing of ethanol vapor. This method is applicable to any FET-based chemical and biological sensor, provides a means to predict the absolute sensor performance limit, and suggests a standardized way to compare LODs and sensitivities of various sensors.
authors.affiliation: Department of Physical Electronics, School of Electrical Engineering, Tel-Aviv University, Ramat-Aviv, 69978, Israel.
authors.forename: Alex
authors.initials: A
authors.lastname: Henning
authors.affiliation: Department of Physical Electronics, School of Electrical Engineering, Tel-Aviv University, Ramat-Aviv, 69978, Israel.
authors.forename: Michel
authors.initials: M
authors.lastname: Molotskii
authors.affiliation: Department of Physical Electronics, School of Electrical Engineering, Tel-Aviv University, Ramat-Aviv, 69978, Israel.
authors.forename: Nandhini
authors.initials: N
authors.lastname: Swaminathan
authors.affiliation: Department of Physical Electronics, School of Electrical Engineering, Tel-Aviv University, Ramat-Aviv, 69978, Israel.
authors.forename: Yonathan
authors.initials: Y
authors.lastname: Vaknin
authors.affiliation: Department of Physical Electronics, School of Electrical Engineering, Tel-Aviv University, Ramat-Aviv, 69978, Israel.
authors.forename: Andrey
authors.initials: A
authors.lastname: Godkin
authors.affiliation: Department of Physical Electronics, School of Electrical Engineering, Tel-Aviv University, Ramat-Aviv, 69978, Israel.
authors.forename: Gil
authors.initials: G
authors.lastname: Shalev
authors.affiliation: Department of Physical Electronics, School of Electrical Engineering, Tel-Aviv University, Ramat-Aviv, 69978, Israel.
authors.forename: Yossi
authors.initials: Y
authors.lastname: Rosenwaks
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation*; D057230:Limit of Detection; D053770:Nanowires / Q000737:chemistry*; D055672:Static Electricity
keywords: Kelvin probe force microscopy; Si nanowires; limit of detection; multiple gate transistors; scanning gate microscopy; sensors