This study presents the performance of monolayer graphene nanomechanical resonators with electrical readout. The researchers demonstrate the fabrication and electrical readout of monolayer graphene resonators and test their response to changes in mass and temperature. The devices show resonances in the MHz range. The resonant frequency is strongly dependent on the applied gate voltage, which can be modeled using a membrane model to determine the mass density and built-in strain. Upon adding or removing mass, changes in both density and strain are observed, indicating that adsorbates impart tension to the graphene. Cooling increases the frequency, and the shift rate can be used to measure the unusual negative thermal expansion coefficient of graphene. The quality factor increases with decreasing temperature, reaching ~10^4 at 5 K. These studies establish the basic attributes of monolayer graphene resonators, laying the groundwork for applications such as high-sensitivity mass detectors. Graphene, discovered in 2004, has attracted attention due to its unique two-dimensional structure and potential applications. Its exceptional mechanical properties and low mass density make it an ideal material for nanoelectromechanical systems (NEMS), which are of interest for both fundamental studies and applications such as force, position, and mass sensing. Recent studies have shown that micron-sized graphene flakes can act as MHz-range NEMS resonators. Electrical readout is important for integration and attractive for many applications. Characterizing the basic attributes of these devices allows detailed modeling of their behavior, crucial for rational device design. The samples are fabricated by locating monolayer graphene flakes on Si/SiO2 substrates, then patterning metal electrodes and etching away the SiO2 to yield suspended graphene. The fabrication method provides control over the lateral dimensions, allowing devices to be either micron-wide sheets or lithographically defined nanoribbons. The etchant diffuses freely under the sheets, removing the SiO2 at the same rate everywhere, so that the distance between the substrate and the suspended sheet is constant (~100 nm) across each device. The portion of each electrode that contacts the graphene is also suspended. The researchers implemented an all-electrical high-frequency mixing approach to actuate and detect mechanical resonances. A DC gate voltage applies static tension to the device, an RF gate voltage drives the motion, and a second RF voltage is applied to the source. The graphene conductance changes with distance from the gate, and motion is detected as a mixed-down current at the difference frequency. The weaker gate response of the conductivity of multilayer graphene makes the use of monolayers advantageous for this method. The study shows that the resonant frequency of the graphene increases with gate voltage, while the resonant frequency of the gold beams is independent of gate voltage. The contrast between the two resonances highlights the unique features of devices with thickness near the atomic scale, such as graphene and single-walled carbon nanotubes. For suspended graphene lengths fromThis study presents the performance of monolayer graphene nanomechanical resonators with electrical readout. The researchers demonstrate the fabrication and electrical readout of monolayer graphene resonators and test their response to changes in mass and temperature. The devices show resonances in the MHz range. The resonant frequency is strongly dependent on the applied gate voltage, which can be modeled using a membrane model to determine the mass density and built-in strain. Upon adding or removing mass, changes in both density and strain are observed, indicating that adsorbates impart tension to the graphene. Cooling increases the frequency, and the shift rate can be used to measure the unusual negative thermal expansion coefficient of graphene. The quality factor increases with decreasing temperature, reaching ~10^4 at 5 K. These studies establish the basic attributes of monolayer graphene resonators, laying the groundwork for applications such as high-sensitivity mass detectors. Graphene, discovered in 2004, has attracted attention due to its unique two-dimensional structure and potential applications. Its exceptional mechanical properties and low mass density make it an ideal material for nanoelectromechanical systems (NEMS), which are of interest for both fundamental studies and applications such as force, position, and mass sensing. Recent studies have shown that micron-sized graphene flakes can act as MHz-range NEMS resonators. Electrical readout is important for integration and attractive for many applications. Characterizing the basic attributes of these devices allows detailed modeling of their behavior, crucial for rational device design. The samples are fabricated by locating monolayer graphene flakes on Si/SiO2 substrates, then patterning metal electrodes and etching away the SiO2 to yield suspended graphene. The fabrication method provides control over the lateral dimensions, allowing devices to be either micron-wide sheets or lithographically defined nanoribbons. The etchant diffuses freely under the sheets, removing the SiO2 at the same rate everywhere, so that the distance between the substrate and the suspended sheet is constant (~100 nm) across each device. The portion of each electrode that contacts the graphene is also suspended. The researchers implemented an all-electrical high-frequency mixing approach to actuate and detect mechanical resonances. A DC gate voltage applies static tension to the device, an RF gate voltage drives the motion, and a second RF voltage is applied to the source. The graphene conductance changes with distance from the gate, and motion is detected as a mixed-down current at the difference frequency. The weaker gate response of the conductivity of multilayer graphene makes the use of monolayers advantageous for this method. The study shows that the resonant frequency of the graphene increases with gate voltage, while the resonant frequency of the gold beams is independent of gate voltage. The contrast between the two resonances highlights the unique features of devices with thickness near the atomic scale, such as graphene and single-walled carbon nanotubes. For suspended graphene lengths from