Gigahertz multimode vibrations in graphene and MoS ₂ nanomechanical resonators at room temperature

Probing and understanding ultrahigh-frequency/gigahertz (UHF/GHz) vibrations in atomic layer nanomechanical resonators holds strong promise for fundamental studies and technological applications, such as sensing, signal processing, and quantum engineering. However, accessing GHz flexural-mode resonances in such devices at room temperature has been challenging. Here, we demonstrate the first measurement of GHz flexural vibrations in graphene and molybdenum disulfide (MoS₂) resonators at room temperature, achieving multimode resonances (<i>f</i>_{<i>m</i>,<i>n</i>}) up to ~1.09 GHz and quality factors (<i>Q</i>_{<i>m</i>,<i>n</i>}) up to ~5400 in multilayer MoS₂ resonators, and <i>f</i>_{<i>m</i>,<i>n</i>} up to ~1.03 GHz with high <i>Q</i>_{<i>m</i>,<i>n</i>} ~4500 in few-layer graphene resonators. Both <i>f</i>s and <i>Q</i>s are the highest among reported atomic layer nanomechanical resonators at room temperature, yielding <i>f</i>_{<i>m</i>,<i>n</i>} × <i>Q</i>_{<i>m</i>,<i>n</i>} ~ 5 × 10¹² Hz. We also reveal a <i>Q</i> scaling law with higher modes, which favors detecting GHz resonances. This study will enable exploiting multiple modes in atomic layer resonators toward resonant sensing and transduction functions at UHF/GHz.