On the modeling of amplitude-sensitive ESR detection using VCO-based ESR-on-a-chip detectors

Chu, A.; Schlecker, Benedikt; Kern, Michal; Goodsell, Justin L.; Angerhofer, Alexander; Lips, K.; Anders, Jens

doi:10.5194/mr-2021-42

Cited by 2 publications

(1 citation statement)

References 30 publications

(37 reference statements)

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“…To extend the benefits of these non-resonant EDMR applications, the aim of this work was to develop and evaluate a compact and portable spectrometer that is capable of performing EDMR measurements in thin-film photovoltaic materials by combining an EPR-on-a-Chip (EPRoC) device, which has been previously employed successfully for in situ and ambient condition EPR applications [14,15], with an ultrasensitive transimpedance amplifier (TIA) on a chip. The EDMR-on-a-Chip (EDMRoC) has been constructed to use the EPRoC to generate the B 1 field required to elicit the EDMR spin-response to investigate thin-film samples relevant for these photovoltaic applications.…”

Section: Introductionmentioning

confidence: 99%

Electrically Detected Magnetic Resonance on a Chip (EDMRoC) for Analysis of Thin-Film Silicon Photovoltaics

Segantini,

Marcozzi,

Djekic

et al. 2023

Magnetochemistry

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Electrically detected magnetic resonance (EDMR) is a spectroscopic technique that provides information about the physical properties of materials through the detection of variations in conductivity induced by spin-dependent processes. EDMR has been widely applied to investigate thin-film semiconductor materials in which the presence of defects can induce the current limiting processes. Conventional EDMR measurements are performed on samples with a special geometry that allows the use of a typical electron paramagnetic resonance (EPR) resonator. For such measurements, it is of utmost importance that the geometry of the sample under assessment does not influence the results of the experiment. Here, we present a single-board EPR spectrometer using a chip-integrated, voltage-controlled oscillator (VCO) array as a planar microwave source, whose geometry optimally matches that of a standard EDMR sample, and which greatly facilitates electrical interfacing to the device under assessment. The probehead combined an ultrasensitive transimpedance amplifier (TIA) with a twelve-coil array, VCO-based, single-board EPR spectrometer to permit EDMR-on-a-Chip (EDMRoC) investigations. EDMRoC measurements were performed at room temperature on a thin-film hydrogenated amorphous silicon (a-Si:H) pin solar cell under dark and forward bias conditions, and the recombination current driven by the a-Si:H dangling bonds (db) was detected. These experiments serve as a proof of concept for a new generation of small and versatile spectrometers that allow in situ and operando EDMR experiments.

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Section: Introductionmentioning

confidence: 99%

Electrically Detected Magnetic Resonance on a Chip (EDMRoC) for Analysis of Thin-Film Silicon Photovoltaics

Segantini,

Marcozzi,

Djekic

et al. 2023

Magnetochemistry

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Rapid-scan electron paramagnetic resonance using an EPR-on-a-Chip sensor

Künstner

Chu²,

Dinse

et al. 2021

Magn. Reson.

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Abstract. Electron paramagnetic resonance (EPR) spectroscopy is the method of choice to investigate and quantify paramagnetic species in many scientific fields, including materials science and the life sciences. Common EPR spectrometers use electromagnets and microwave (MW) resonators, limiting their application to dedicated lab environments. Here, novel aspects of voltage-controlled oscillator (VCO)-based EPR-on-a-Chip (EPRoC) detectors are discussed, which have recently gained interest in the EPR community. More specifically, it is demonstrated that with a VCO-based EPRoC detector, the amplitude-sensitive mode of detection can be used to perform very fast rapid-scan EPR experiments with a comparatively simple experimental setup to improve sensitivity compared to the continuous-wave regime. In place of a MW resonator, VCO-based EPRoC detectors use an array of injection-locked VCOs, each incorporating a miniaturized planar coil as a combined microwave source and detector. A striking advantage of the VCO-based approach is the possibility of replacing the conventionally used magnetic field sweeps with frequency sweeps with very high agility and near-constant sensitivity. Here, proof-of-concept rapid-scan EPR (RS-EPRoC) experiments are performed by sweeping the frequency of the EPRoC VCO array with up to 400 THz s−1, corresponding to a field sweep rate of 14 kT s−1. The resulting time-domain RS-EPRoC signals of a micrometer-scale BDPA sample can be transformed into the corresponding absorption EPR signals with high precision. Considering currently available technology, the frequency sweep range may be extended to 320 MHz, indicating that RS-EPRoC shows great promise for future sensitivity enhancements in the rapid-scan regime.

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On the modeling of amplitude-sensitive ESR detection using VCO-based ESR-on-a-chip detectors

Cited by 2 publications

References 30 publications

Electrically Detected Magnetic Resonance on a Chip (EDMRoC) for Analysis of Thin-Film Silicon Photovoltaics

Electrically Detected Magnetic Resonance on a Chip (EDMRoC) for Analysis of Thin-Film Silicon Photovoltaics

Rapid-scan electron paramagnetic resonance using an EPR-on-a-Chip sensor

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