Capacitive micromachined ultrasonic transducer (CMUT) array with single-layer graphene membrane

A capacitive micromachined ultrasonic transducer (CMUT) with a graphene membrane is reported. The CMUT membranes were commonly made from very thin silicon nitride or metal material. To date, no graphene CMUT has been successfully used. In this reported work, a photomask were used for the cavity pattern to make a 1 mu m layer EPON SU-8 photoresist on the silicon substrate. Then a single-layer graphene were tranferred directly to be attached to the EPON SU-8 cavity layer to form the CMUT with a graphene membrane. The resonance frequency was measured to be 95 MHz in air.