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We have fabricated circular silicon nitride drums of varying diameter (20 μm to 1 mm) and thickness (15 nm-75 nm) using electron beam lithography and measured the dissipation (Q-1) of these amorphous silicon nitride resonators using optical interferometric detection. We observe that the dissipation is strongly dependent on mode type for relatively large, thick membranes as predicted by the current models of dissipation due to clamping loss. However, this dependence is drastically reduced for smaller or thinner resonators, with thinner resonators showing higher quality factors, for low order modes. Highest quality factors that can be reached for these thin resonators seems be limited by an intrinsic mechanism and scales linearly with the diameter of the membrane. Our results are promising for mass sensing and optomechanical applications where low mass and high Qs are desirable. [ABSTRACT FROM AUTHOR]

Resonant mechanics of high quality factor (Q) graphene coated silicon nitride devices have been explored using optical and electrical transduction schemes. With the addition of the graphene layer, we retain the desirable mechanical properties of silicon nitride but utilize the electrical and optical properties of graphene to transduce and tune the resonant motion by both optical and electrical means. By positioning the graphene-on-silicon-nitride drums in a tunable optical cavity, we observe position dependent damping and resonant frequency control of the devices due to optical absorption by graphene. [ABSTRACT FROM AUTHOR]

We have fabricated large (≤400 μm diameter) high tensile stress SiN membrane mechanical resonators and measured the resonant frequency and quality factors (Q) of different modes of oscillation using optical interferometric detection. We observe that the dissipation (Q-1) is limited by clamping loss for pure radial modes, but higher order azimuthal modes are limited by a mechanism which appears to be intrinsic to the material. The observed dissipation is strongly dependent on size of the membrane and mode type. Appropriate choice of size and operating mode allows the selection of optimum resonator designs for applications in mass sensing and optomechanical experiments. [ABSTRACT FROM AUTHOR]