Monolayer MoS$_2$ Strained to 1.3\% with a Microelectromechanical System

TL;DR

This paper introduces a novel transfer technique for atomically thin MoS$_2$ onto MEMS devices, enabling controlled strain application exceeding 1.3\%, and demonstrates the strain's effects via Raman and Photoluminescence spectra.

Contribution

The authors developed a new transfer method compatible with MEMS that allows precise, crack-free placement of 2D materials and achieved the first successful strain of over 1.3\% in MoS$_2$ using MEMS.

Findings

Strain of over 1.3\% achieved in MoS$_2$ using MEMS.

Good agreement between experimental Raman/PL spectra and literature.

Enhanced fabrication yield and reduced processing time.

Abstract

We report on a modified transfer technique for atomically thin materials integrated onto microelectromechanical systems (MEMS) for studying strain physics and creating strain-based devices. Our method tolerates the non-planar structures and fragility of MEMS, while still providing precise positioning and crack free transfer of flakes. Further, our method used the transfer polymer to anchor the 2D crystal to the MEMS, which reduces the fabrication time, increases the yield, and allowed us to exploit the strong mechanical coupling between 2D crystal and polymer to strain the atomically thin system. We successfully strained single atomic layers of molybdenum disulfide (MoS$_2$) with MEMS devices for the first time and achieved greater than 1.3\% strain, marking a major milestone for incorporating 2D materials with MEMS We used the established strain response of MoS$_2$ Raman and Photoluminescence spectra to deduce the strain in our crystals and provide a consistency check. We found good comparison between our experiment and literature.