SMO	Semiconductor metal oxide
RGO	Reduced Graphene Oxide
FESEM	Field emission scanning electron microscopy
XRD	X-ray diffractometer
QCM	Quartz Crystal Microbalance
CMUT	Capacitive Micro-machined Ultrasonic Transducer
FBAR	Film Bulk Acoustic Resonator
AC	Alternating current
EIS	Electrochemical impedance spectroscopy
RH	Relative humidity
PCB	Printed circuit board