Large-Scale Arrays of Single- and Few-Layer MoS2 Nanomechanical Resonators

TL;DR

This paper demonstrates the fabrication of large-scale arrays of suspended MoS2 nanomechanical resonators with high frequency and quality, using a water-assisted transfer process that ensures high yield, uniformity, and minimal chemical exposure.

Contribution

It introduces a novel water-assisted lift-off and transfer method for large-scale MoS2 resonator arrays, achieving high performance and uniformity with minimal chemical processing.

Findings

Resonators operate up to ~120 MHz in the VHF band.

High figures-of-merit up to f_0*Q ~ 3*10^10 Hz.

Low pre-tension levels of ~15 mN/m in devices.

Abstract

We report on fabrication of large-scale arrays of suspended molybdenum disulfide (MoS2) atomic layers, as two-dimensional (2D) MoS2 nanomechanical resonators. We employ a water-assisted lift-off process to release chemical vapor deposited (CVD) MoS2 atomic layers from a donor substrate, followed by an all-dry transfer onto microtrench arrays. The resultant large arrays of suspended single- and few-layer MoS2 drumhead resonators (0.5 to 2um in diameter) offer fundamental resonances (f_0) in the very high frequency (VHF) band (up to ~120MHz) and excellent figures-of-merit up to f_0*Q ~ 3*10^10Hz. A stretched circular diaphragm model allows us to estimate low pre-tension levels of typically ~15mN/m in these devices. Compared to previous approaches, our transfer process features high yield and uniformity with minimal liquid and chemical exposure (only involving DI water), resulting in high-quality MoS2 crystals and exceptional device performance and homogeneity; and our process is readily applicable to other 2D materials.