Light-induced persistent resonance frequency shift of MoS2 mechanical resonator

We investigate light-induced persistent resonance frequency shift on MoS2 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 MoS2 similar to the persistent photoconductivity. The trapped holes screen the electrostatic force acting on MoS2, which results in the reduction of the tension of MoS2. The downshift can be eliminated by applying the excess voltage pulse to MoS2 to induce Joule heating.

Automated summary

The study found that on MoS2 mechanical resonators, there is a persistent resonance frequency downshift after light irradiation, lasting for more than 20 minutes. This downshift is caused by photogenerated holes trapped at defects or contamination on MoS2, similar to persistent photoconductivity, which can be eliminated by applying excess voltage pulse.