A triboelectric charge top-gated graphene transistor

- The response of graphene channel to the charges on a stimulator and the in situ generated charges are different.
- The in situ generated triboelectric charges on a polymer passive layer induce a stepwise change of the channel resistance.
- The results in this work suggest two possible operation models for the tribo-charge top-gate graphene channel.

A graphene channel with polymer polymethyl methacrylate (PMMA) or Polydimethylsiloxane (PDMS) passive layer were fabricated on a Si/SiO2 substrate. The gate-effect of triboelectric charges on a foreign stimulator and in situ generated triboelectric charges on the passive layer are tested by controlling the foreign stimulator (PDMS or Acrylic plate) touch or not with the passive layer. When the negatively charged PDMS (positively charged Acrylic) stimulator approach and leave the device without touching the passive layer, the channel resistance shows a pulsed decrease (increase) with amplitude less than 1%. When the stimulator has a temporary touch with the passive layer, the in situ generated triboelectric charges on the PMMA (PDMS) passive layer cause stepwise increase (decrease) of the channel resistance. The amplitude of the resistance change steps of the device with PMMA passive layer (2 μm in thickness) is about one order larger for than that of the device with PDMS passive layer (about 60 μm in thickness). The significant different response of the device depending on whether the stimulator touches or not with the passive layer suggests two possible operation models for the tribo-charge top-gated graphene channel. It may enable diverse design of tactile sensors and pressure sensors based on the tribotronic effect.

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