Positron charge sensing using a double-gated graphene field effect transistor

Paz Or, T. R. Devidas, Takashi Taniguchi, Kenji Watanabe, Iris Sabo-Napadesky, Sharon May-Tal Beck, Guy Ron, Hadar Steinberg

Research output: Contribution to journalReview articlepeer-review

3 Scopus citations

Abstract

We utilize a high-mobility double-gated graphene field-effect transistor to measure the accumulated charge created by positron annihilation in its back-gate. The device consists of an exfoliated graphene flake stacked between two hexagonal boron nitride flakes placed on a 1 cm2 substrate of 500 μm thick conducting p-doped Si capped by 285 nm-thick SiO2. The device is placed in close proximity to a 780 kBq 22Na positron source emitting a constant flux of positrons. During the measurement, positrons annihilate within the back-gate, kept floating using a low-capacitance relay. The accumulated positive charge capacitively couples to the graphene device and builds a positive voltage, detectable through a shift in the top-gate dependent graphene resistance characteristic. The shift in the position of the top-gate Dirac peak is then used for extracting the exact voltage buildup and quantitative evaluation of the accumulated charge. Reaching a positron current sensitivity of ∼1.2 fA/Hz, detected over 20 min, our results demonstrate the utility of two-dimensional layered materials as probes for charging dynamics of positrons in solids.

Original languageEnglish
Article number015002
JournalReview of Scientific Instruments
Volume93
Issue number1
DOIs
StatePublished - 1 Jan 2022
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2022 Author(s).

Funding

Devices for this study were fabricated at the Center for Nanoscience and Nanotechnology, the Hebrew University. Funding for this work was provided by the IAEC through Pazy Grant No. 328/20 and by Israel Science Foundation Grant No. 861/19. P.O. was supported by a fellowship by the Ministry of Science and Technology, Israel. T.R.D. acknowledges support from the Lady Davis Postdoctoral Fellowship program. K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan (Grant No. JPMXP0112101001) and JSPS KAKENHI (Grant Nos. JP19H05790 and JP20H00354).

FundersFunder number
Japan Society for the Promotion of ScienceJP20H00354, JP19H05790
Ministry of Education, Culture, Sports, Science and TechnologyJPMXP0112101001
Hebrew University of Jerusalem
Israel Science Foundation861/19
Ministry of science and technology, Israel
Israel Atomic Energy Commission328/20

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