Light-induced persistent resonance frequency shift of MoS 2 mechanical resonator

We investigate light-induced persistent resonance frequency shift on MoS 2 mechanical resonators towards optically tunable nano-electro-mechanical systems with optical memory function. After the termination of light irradiation, the resonance frequency shifts downwards and the downshift is maintained for more than 20 min. This behavior is induced by trapped photogenerated holes at defects or contamination on MoS 2 similar to the persistent photoconductivity. The trapped holes screen the electrostatic force acting on MoS 2 , which results in the reduction of the tension of MoS 2 . The downshift can be eliminated by applying the excess voltage pulse to MoS 2 to induce Joule heating.