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Abstract Surface acoustic waves (SAWs) that propagate on the surface of a solid at MHz frequencies are widely used in sensing, communication, and acoustic tweezers. However, their properties are difficult to be tuned electrically, and current devices suffer from complicated configurations, complicated tuning mechanisms, or small ranges of tunability. Here a structure featuring a thin‐film transistor configuration is proposed to achieve electrically tunable SAW propagation based on conductivity tuning. When a DC gate voltage is applied, the on‐site conductivity of the piezoelectric substrate is modulated, which leads to velocity and amplitude tuning of SAWs. The use of carbon nanotubes and crystalline nanocellulose as the channel and gate materials results in high tuning capacity and low gate voltage requirement. The tunability is manifested by a 2.5% phase velocity tuning and near 10 dB on/off switching of the signals. The proposed device holds the potential for the next generation SAW‐based devices.
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A Tunable Surface Acoustic Wave Device on Zinc Oxide via acoustoelectric interaction with AIGaN/GaN 2DEG
Surface acoustic wave devices have many applications in signal processing, radio frequency (RF) communications, and sensing [1]. The most common utilization of these devices is for filtering electromagnetic signals in communications systems. However, since the physical dimensions of the inter-digitated transducers (IDT) determine the frequency response, it is very difficult to attain tunable devices for programmable applications. Great effort has been made to achieve an integrated solution to this in III-V semiconductors. One such work utilizes the piezoelectric the GaN buffer layer in an AlGaN/GaN epi for acoustic propagation, while a metal-insulator-semiconductor (MIS) structure is used to tune the SAW response [2]. Unfortunately, the MIS structure results in a weak interaction only achieving a phase tunability of 0.07%. Recent work, uses thin film Zinc Oxide (ZnO) as a piezoelectric on top of n-type ZnO on GaN achieving a high tunability of. 9% [3]. In this work, we demonstrate a ZnO on AIGaN/GaN heterostructure capable of achieving high tunability as well as impacting properties of the SAW filter not previously reported.
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- Award ID(s):
- 1641100
- PAR ID:
- 10113068
- Date Published:
- Journal Name:
- Device Research Conference 2019
- Page Range / eLocation ID:
- 111 to 112
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/DRC46940.2019.9046437
