Electromechanical mode imaging of MoS2 drum resonators

Abstract

Recent studies of optomechanical resonators based on 2D materials, are mainly focused on their response at a fixed point. Most studies focus on the oscillating behaviour of the centre of the system, where the amplitude of the fundamental mode is maximum. This methodology overlooks the spatial distribution of higher frequency oscillation modes in which the nodal lines cross the central point. These modes are of interest as they contain information of the stress and defect profiles, among other physical properties of the resonator/cavity system. Understanding the frequency response and spatial distribution of these modes is key both for fundamental science but also for the technological exploitation of these devices. In this work, we study the mechanical modes of few-layer MoS _2 electromechanical resonators down to 5 K with circular and rectangular boundary conditions. We have developed a novel technique to perform radio frequency spectral mapping of the resonators’ optical response as they oscillate in real time. With this technique, we gain direct insight on the spatial distribution of the strain fields in the modal spectra of our devices.

Keywords

• MEMS
• two-dimensional materials
• optomechanics
• acoustics
• resonators