Controlling the properties of surface acoustic waves using graphene
Springer Verlag (Germany)
The author(s) Surface acoustic waves (SAWs) are elastic waves that propagate on the surface of a solid, much like waves on the ocean, with SAW devices used widely in communication and sensing. The ability to dynamically control the properties of SAWs would allow the creation of devices with improved performance or new functionality. However, so far it has proved extremely difficult to develop a practical way of achieving this control. In this paper we demonstrate voltage control of SAWs in a hybrid graphene-lithium niobate device. The velocity shift of the SAWs was measured as the conductivity of the graphene was modulated using an ion-gel gate, with a 0.1% velocity shift achieved for a bias of approximately 1 V. This velocity shift is comparable to that previously achieved in much more complicated hybrid semiconductor devices, and optimization of this approach could therefore lead to a practical, cost-effective voltage-controlled velocity shifter. In addition, the piezoelectric fields associated with the SAW can also be used to trap and transport the charge carriers within the graphene. Uniquely to graphene, we show that the acoustoelectric current in the same device can be reversed, and switched off, using the gate voltage. [Figure not available: see fulltext.]
The authors would like to acknowledge the financial support of the Royal Society (No. RG100570). G. R. N. also acknowledges the support of the UK Engineering and Physical Sciences Research Council through a Fellowship in Frontier Manufacturing (No. EP/J018651/1). Electronic Supplementary Material: Supplementary material (experimental data obtained for other devices) is available in the online version of this article at http://dx.doi.org/10.1007/s12274-015-0947-z.
This is the author accepted manuscript. The final version is published with open access at Springerlink.com via http://dx.doi.org/10.1007/s12274-015-0947-z
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