Fig. 4: Electrical simulations of the Pizeoelectric resonator.
From: Ultra-low-noise microwave to optics conversion in gallium phosphide
Top: stationary electrostatic simulation with a cut plane showing the electric potential. The cut plane is perpendicular to the [110] axis in the crystal. The simulated geometry consists of the piezoelectric resonator (center) with two tapered ends and two side pads. Both the resonator and the pads consist of a 230 nm-thick gallium phosphide device layer. On top of the device, layer is a 40 nm thick film of molybdenum-rhenium (MoRe). The structure is surrounded by an airbox and 1 μm underneath, a 1 μm-thick block of GaP is placed to account for the effect of the substrate. We extract a capacitance of \({C}_{{{{{{{{\rm{res}}}}}}}}}\) to be 0.17 fF. Bottom: Simulated admittance curve for the same structure. We perform a frequency-domain study where we sweep the drive frequency across the breathing mode of the resonator (Fig. 1d). From the frequencies at which the series (fs) and parallel (fp) resonances occur, we calculate \({k}_{{{{{{{{\rm{eff}}}}}}}}}^{2}=1.59\times 1{0}^{-6}\).
