Surface Engineering of Graphene SAW Gas Sensor for Effective Health Monitoring

To improve the quality of modern life in the current society, low-power and reliable gas sensing technology is necessary to monitor human health in real time through relevant respiratory biomarkers. However, due to the relatively small concentration and rich interfering substances, accurate identification of selective gas molecules is quite challenging. Herein, we have fabricated monolayer graphene surface acoustic gas sensor (G-SAW) with love wave for effective detection of acetone gas molecules under room temperature. We have deposited different thickness of SiO₂ as the guiding layer which reduces the noise and insertion loss in fabricated device. G-SAW showed an enhanced gas response towards the acetone gas molecules (800 ppt) at room temperature. The primary sensing mechanism of G-SAW sensor is based on elastic and acoustic-electric effect which is attributed to the adsorption of acetone gas molecules on the surface of graphene. The acetone which has large dipole moment (2.69) and ionic radii easily adsorb on graphene by forming C-O bonding which leads to p-doping and shift towards high frequency in the G-SAW gas sensor. This work provides a potential strategy for detection biomarkers from human breath and diagnose the diabetic disease in human body.