Non-contact Measurement of DC Potentials with Applications in Static Charge Imaging

Pouryazdan, Arash; Costa, J.; Spina, Filippo; Prance, R. J.; Prance, H.; Münzenrieder, Niko

doi:10.1109/sensors47125.2020.9278841

Cited by 4 publications

(3 citation statements)

References 20 publications

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“…The sensing area of the electrometer is 5 µm in diameter. A similar system was previously used to quantify local DC voltage variations [23], and to acquire high fidelity maps of electric potentials [24]. The electrometer is raster scanned at a constant height of 50 µm above the conductive thin-film.…”

Section: Methodsmentioning

confidence: 99%

Non-contact thin-film sheet conductance measurement based on the attenuation of low frequency electric potentials

Pouryazdan

Prance

et al. 2021

J. Phys. D: Appl. Phys.

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Conductivity is a fundamental property of materials; in particular the precise quantification of electrical sheet resistance is essential for the development of electronic thin-film devices. Conventionally, resistive probes are used to perform the corresponding measurements. However, non-invasive methods are more desirable as they minimize the required sample preparation, as well as geometrical influences. Existing non-contact conductivity measurements mostly rely on the transmission of electromagnetic waves through conductive thin-films. Hence, they only characterize translucent samples at high frequencies. We present an alternative technique based on the attenuation of low frequency 10 kHz electric fields. The approach is used to quantify the field-effect induced conductivity variation of a flexible indium-gallium-zinc-oxide semiconductor film. A custom-built high-impedance electrometer is used to capacitively measure the attenuation of an alternating electric field passing through the film. The obtained data is discussed and related to the absolute conductivity with the aid of two bespoke models describing the impedance mismatch between the sample and its surroundings. The sheet conductivity is modulated and measured from 660 nS to 116 µS while conventional DC current/voltage measurements serve as a reference. Both methods show a high degree of correlation to the reference measurements. Unlike techniques based on light, the low frequency signal used here resembles quasi-static characteristics, and enables the direct measurement of DC parameters.

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Section: Methodsmentioning

confidence: 99%

Non-contact thin-film sheet conductance measurement based on the attenuation of low frequency electric potentials

Pouryazdan

Prance

et al. 2021

J. Phys. D: Appl. Phys.

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“…Because electrical field lines always enter and exit the surface of an electrode perpendicularly, concentrating them is possible. In addition to the efficient use of shields, Prance et al showed an example of how to focus the electrode of a passive electric field sensor using a needle with a 50 µm tip [11]. A different approach is to couple the electrode to a different object, which henceforth acts as the electrode, instead of forming the electrode on the sensor itself.…”

Section: Physical Optimizationmentioning

confidence: 99%

Optimizations for Passive Electric Field Sensing

Wilmsdorff

Kuijper

2022

Sensors

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Passive electric field sensing can be utilized in a wide variety of application areas, although it has certain limitations. In order to better understand what these limitations are and how countervailing measures to these limitations could be implemented, this paper contributes an in-depth discussion of problems with passive electric field sensing and how to bypass or solve them. The focus lies on the explanation of how commonly known signal processing techniques and hardware build-up schemes can be used to improve passive electric field sensors and the corresponding data processing.

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“…The ultra-high input resistance of EPS (≈ 0.1 TΩ) along with the ultra-low input capacitance (≈0.3 fF) enables the measurements of AC potentials with frequencies from 50 mHz to 330 MHz and a noise floors as low as 3.5 nV/ √ Hz [6], [11], [12]. It is also possible to measure DC potentials with microscopic resolution using EPS [13]. The capabilities of EPS technology to image electric fields have been previously demonstrated by integrating such sensors into non-contact scanning electric potential microscopes (SEPM).…”

Section: Introductionmentioning

confidence: 99%

Design and Characterisation of a Non-Contact Flexible Sensor Array for Electric Potential Imaging Applications

Pouryazdan¹,

Costa²,

García-García³

et al. 2021

IEEE Sensors J.

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Capacitive non-contact imaging of electric fields and potentials with micro-metre resolution can provide relevant insights into material characterisation, structural analysis, electrostatic charge imaging and bio-sensing applications. However, scanning electric potential microscopes have been confined to rigid and single-probe devices, making them slow, prone to mechanical damage and complex to fabricate. In this work, we present the design and characterisation of a novel 5-element flexible array of electric potential probes with spatial resolution down to 20 µm to speed up the scanning time. This was achieved by combining flexible thin-film probes for active guarding and shielding with state-of-the art discrete conditioning circuits. The potential of this approach is showcased by using the fabricated array to image latent fingerprints deposited on an insulating surface by contact electrification, obtain the surface topography of conductive samples and to visualise local dielectric variations.

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Non-contact Measurement of DC Potentials with Applications in Static Charge Imaging

Cited by 4 publications

References 20 publications

Non-contact thin-film sheet conductance measurement based on the attenuation of low frequency electric potentials

Non-contact thin-film sheet conductance measurement based on the attenuation of low frequency electric potentials

Optimizations for Passive Electric Field Sensing

Design and Characterisation of a Non-Contact Flexible Sensor Array for Electric Potential Imaging Applications

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