Graphene-based positron charge sensor

P. Or, D. Dribin, T. R. Devidas, A. Zalic, K. Watanabe, T. Taniguchi, S. May-Tal Beck, G. Ron, H. Steinberg*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


We utilize a graphene field-effect transistor to measure back-gate charging by positrons. The device consists of an exfoliated graphene flake transferred onto hexagonal Boron Nitride, placed on a 1 cm2 substrate of 500 μm thick conducting p-Si capped by 285 nm-thick SiO2. It is placed at close proximity to a 25 μCi 22Na positron source emitting a constant flux of positrons, which during the measurement annihilate within the back-gate. We demonstrate that when the back-gate is allowed to float, the charging current of ≈20 fA causes the buildup of positive charge which capacitively couples to the graphene device and is detected as a variation in the two-terminal conductance. Furthermore, a prolonged exposure to positrons causes a shift in the graphene transport characteristics, associated with local charges at the immediate environment of the graphene flake. Our results demonstrate the utility of two-dimensional layered materials as probes for charging dynamics of positrons in solids.

Original languageAmerican English
Article number154101
JournalApplied Physics Letters
Issue number15
StatePublished - 8 Oct 2018

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