Photoresponse of the AlN-Based SAW Device on Polymeric and Silicon Substrates
Photoresponse of the AlN-Based SAW Device on Polymeric and Silicon Substrates
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DOI：
10.1109/jsen.2020.2992814
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发表时间：
2021-04-15
影响因子：
4.3
通讯作者：
Bhethanabotla, Venkat R.
中科院分区：
文献类型：
--
作者：
Lamanna, Leonardo;Rizzi, Francesco;Bhethanabotla, Venkat R.
本文研究了铝基压电表面声波（SAW）延迟线器件在IR-Vis-UV范围内的光响应。在硅刚性衬底和柔性聚萘二甲酸乙二醇酯衬底上溅射制备了氮化铝（AlN）压电薄膜。通过测量传递函数S-21和激光多普勒振动仪的表征，研究了这两种器件的电声响应。受IR-Vis-UV光刺激的硅基SAW器件，由于光伏效应，其带外插入损耗受到强烈影响。建立了带外损耗与材料导纳变化之间的数学模型。相比之下，基于PEN的SAW器件，由于衬底的聚合物性质，在带外损耗方面没有表现出任何变化。此外，当暴露在紫外光下时，在所有器件中都观察到瑞利和兰姆共振模式的频率下降，这是由于AlN压电层中光致电子的筛选导致声波速度降低。据我们所知，这是第一次在IR-Vis-UV范围内利用SAW的光响应研究，提出了一种基于柔性AlN的SAW器件的紫外光检测新模式。这些设备的进一步发展可以导致基于远程SAW设备的新型光传感器，从紫外到红外。
This paper shows the optical photoresponse in the IR-Vis-UV range of a AlN-based piezoelectric surface acoustic wave (SAW) delay-line device. The piezoelectric aluminum nitride (AlN) thin film has been sputtered on both silicon rigid substrate and flexible polyethylene naphthalate (PEN) substrate. Both devices have been investigated in their electroacoustic response, by measuring the transfer function S-21 and by laser Doppler vibrometer characterization. The silicon based SAW devices, stimulated by the IR-Vis-UV light, are strongly affected in the out-of-band insertion loss due to the photovoltaic effect. A mathematical model has been implemented to correlate the out-of-band loss with the material's electrical admittance change. In contrast PEN based SAW devices, due to the polymeric nature of the substrate, did not show any variation in the out-of-band loss. Moreover, when exposed to UV light, a frequency downshift of the Rayleigh and Lamb resonances modes have been observed in all the devices, due screening of the photoinduced electrons in the AlN piezoelectric layer which induces an acoustic wave velocity reduction. To the best of our knowledge, this is the first photoresponse study exploiting SAW in the range IR-Vis-UV, suggesting a new detection mode of UV light by a flexible AlN based SAW device. Further development of these devices can lead to a new class of light sensors from UV to IR, based on remote SAW devices.