Scheme of the three polymer MEMS bridge configurations types (a) PEDOT:PSS/PMMA (≡ PEDOT); (b) PEDOT:PSS/CNT/PMMA (≡ CNT1); and (c) (PEDOT:PSS/CNT)×2/PMMA (≡ CNT2).
Schematic diagram of main steps of the micro-fabrication process of PEDOT:PSS/CNT/PMMA (CNT1) bridges (longitudinal cross section and top view). The optical micrographs on the right were taken on the correspondingly labeled steps.
SEM micrograph of a CNT1 bridge with an air gap of 1.3 μm, (d), a length of 47 μm (L), a width of 10 μm (w), and a thickness of 520 nm (h).
Characteristic resonance peaks of the fundamental flexural mode of electrostatically actuated and optically detected of PEDOT:PSS/PMMA (PEDOT), PEDOT:PSS/CNT/PMMA (CNT1), and (PEDOT:PSS/CNT)×2/PMMA (CNT2) bridges with L = 47 μm, w = 10 μm, and h = 500 nm. The right panel shows the resonant peak of a n+-a-Si:H bridge (L = 30 μm, w = 10 μm, and h = 300 nm) for comparison. A table with the calculated (EI)eff values for each polymer bridge type is shown as an inset. The marker indicates the calculated f res according to Eq. (1) (see text for details).
Bubble graph of the resonance frequency squared (f res)2 hysteresis as a function of applied DC voltage squared (V DC)2 for: (a) a n+-a-Si:H bridge (L = 30 μm, w = 8 μm, and h = 300 nm); (b) a PEDOT (L = 32 μm); (c) a CNT1 bridge (L = 37 μm,); and (d) a CNT2 bridge (L = 47 μm). In each plot, the diameter of the bubbles is proportional to the respective Q value (the value is not normalized between plots). Lines are linear fits for each cycle. The AC voltage was kept at 1.26 V.
Resonance frequency shift (%) hysteresis curve as a function of the measurement temperature T for a n+-a-Si:H bridge (L = 30 μm and w = 8 μm), a PEDOT bridge (L = 67 μm), and a CNT2 bridge (L = 47 μm).
Resonance frequency shift (%) (left column) and quality factor (right column) as a function of ambient pressure during measurement for different L values: ((a) and (b)) PEDOT; ((c) and (d)) CNT1; and ((e)-(f)) CNT2 resonators (V DC = 10 V and V AC = 1.26 V). Lines correspond to a free molecular flow regime model.
(a) Resonance frequency shift and (b) quality factor as a function of the number of resonant cycles for PEDOT, n+-a-Si:H, CNT1, and CNT2 bridges.
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