Solidly Mounted Resonators with Ultra-High Operating Frequencies Based on 3R-MoS_2 Atomic Flakes

摘要

Conventional bulk and thin piezoelectric materials based film bulk acousticresonators (FBARs) are facing an insurmountable challenge for millimetricfrequency applications due to the poor piezoelectric properties of the materialswhen their thickness reaches the sub-micron regime. Novel FBARs forultra-high working frequencies are in urgent demand to meet the requirementsof the fast-growing 5/6G telecommunication techniques. Recentadvances in 2D piezoelectric nanomaterials create an opportunity in thisperspective. Here, the first FBAR chip based on 2D 3R-MoS_2 ultrathinpiezoelectric flakes with a solidly mounted resonator (SMR) architectureis reported. The typical resonant frequency for an SMR device based on≈200 nm 3R-MoS_2 flake reaches over 25 GHz with high reproducibility.Theoretical and finite element analysis suggest that the observed resonanceis of longitudinal acoustic modes. This study demonstrates for the first timethat the access to 2D piezoelectric nanomaterials makes high performancepiezoelectric devices feasible for various promising applications includinghigh-speed telecommunication, acousto-optic, and sensor fields,etc.