Micro-Scaled Acoustic Wave Sensor based on Suspended 2D van der Waals Materials

초록

Layered two-dimensional (2D) materials have been attracted much attention for the most promising future electronic materials due to their outstanding physical and electrical properties. For example, graphene shows outstanding electrical and mechanical properties, such as 100 times higher electron mobility than silicon (~200,000 cm2/Vs), 200 times stronger mechanical strength than steel, and excellent flexibility in the material itself as well. Although the electrical performance of graphene is maintained even during the stretching and folding test, it might be a drawback for realizing pressure sensor and acoustic wave sensor. From these reasons, employing semiconducting transition metal dichalcogenides (TMDCs) as sensing sites will be a better option to achieve highly sensitive and reactive acoustic wave sensor for the air vibration (sound). In this study, we demonstrate several suspended 2D van der Waals materials based acoustic wave sensors. For the device fabricating, ~10 um separated two glass mesa structures were fabricated on the substrate, and the metal source/drain (SD) electrodes were deposited on each mesa area by using shadow mask technique. And then, 2D layered materials were transferred and located on across the SD pad electrodes to construct the suspended active channel region. The real-time current measurement was conducted to evaluate the sensing properties for the acoustic wave (sound) by using the semiconductor parameter analyzer (Agilent 4156B) and probe station system.