Temperature-Compensated High-Sensitive Graphene Fabry–Perot Acoustic Sensor

Graphene-based Fabry-Perot (F-P) acoustic sensor exhibits excellent performance with high sensitivity and compact dimensions. However, temperature fluctuations compromise its thermal stability of sensitivity due to the changes in cavity length. Herein, a simple and portable graphene-based F-P acoustic sensor with quartz cavity structure (QCS) is developed to address this problem. Acoustic tests show that the cavity length change of the fabricated sensor with QCS is significantly decreased to 3.1 nm/°C in the tested range of 20–80 °C, 95 times smaller than a referenced F-P acoustic sensor with ceramic cavity structure (CCS). The measured frequency response variation (75.6% in the range of 0.1–18 kHz) and sensitivity variation (0.46%/°C at a typical frequency of 1 kHz) are 1.8 times and 2.3 times smaller than the results for the latter, respectively. Moreover, the maximum mechanical sensitivity (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S_M</i>) at 20 °C is up to 395.99 nm/Pa@17 kHz in the aforementioned frequency range, which is at least 147% higher than the state-of-the-art F-P acoustic sensors reported previously. The as-fabricated temperature self-compensated sensor demonstrates potential for weak acoustic detection in varying temperature environments.