Controlling the properties of surface acoustic waves using graphene
Controlling the properties of surface acoustic waves using graphene
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DOI：
10.1007/s12274-015-0947-z
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发表时间：
2016-03-01
期刊：
影响因子：
9.9
通讯作者：
Nash, Geoffrey R.
中科院分区：
文献类型：
--
作者：
Bandhu, Lokeshwar;Nash, Geoffrey R.
声表面波 (SAW) 是在固体表面传播的弹性波，就像海洋中的波浪一样，SAW 设备广泛用于通信和传感领域。动态控制 SAW 属性的能力将允许创建具有改进性能或新功能的设备。然而，到目前为止，事实证明开发一种实现这种控制的实用方法极其困难。在本文中，我们演示了混合石墨烯-铌酸锂器件中 SAW 的电压控制。当使用离子凝胶门调制石墨烯的电导率时，测量了 SAW 的速度变化，在大约 1 V 的偏置下实现了 0.1% 的速度变化。这种速度变化与之前在更复杂的混合半导体器件中实现的速度变化相当，因此，这种方法的优化可以带来实用的、经济高效的压控速度变化器。此外，与SAW相关的压电场也可用于捕获和传输石墨烯内的电荷载流子。石墨烯的独特之处在于，我们证明同一器件中的声电流可以使用栅极电压反转并关闭。
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.