Platinum composite nanowires for ultrasensitive mass detection

Abstract

Platinum (Pt) composite nanowires were grown on the tip of tungsten (W) microprobes by focused-electron-beam induced chemical vapor deposition (FEB-CVD). An electrical field was used to drive a transversal mechanical vibration of the nanowires. Such nanowire vibrations were found to display the first and second harmonic resonances with frequencies in the range of tens of MHz. The Young's modulus of the nanowires was estimated to be in the range of (1.4 ± 0.1) × 102 GPa to (4.7 ± 0.2) × 102 GPa, dependent on the wire size. A mass responsivity of 2.1 × 1021 Hz/kg was demonstrated with the minimum detectable mass of about 0.4 attogram. Our results indicated the potentials of FEB-CVD for the fabrication of nano-balances on any surface for ultra-sensitive mechanical applications.

From MoO2@MoS2 Core–Shell Nanorods to MoS2 Nanobelts

“…[35] No scrolling can be attributed to the high stiffness of single-layer MoS 2 . [37][38][39] In addition, all of the decoupled MoS 2 -shells turned into monolayer MoS 2 nanobelts upon the removal of PMMA by using acetone solution ( Figure S1a, Supporting Information).…”

Mechanical Properties of 3D Nanostructures Obtained by Focused Electron/Ion Beam-Induced Deposition: A Review

“…Close to resonance, the pillar starts vibrating with a visible amplitude, which is reflected by a Gaussian peak in the amplitude versus frequency diagram (top). Alternatively, the excitation can be applied via electrostatic forces by using an electrode as was performed in the experiments shown in Figure 9a-g. Hao et al [90] were able to excite also the second harmonic frequency f 2 (the pre-factor becomes (4.69409) 2 in Equation (14) in their FEBID pillars, as shown in Figure 9c. A peculiar feature of their experiment was that the pillar had a very non-uniform base part with large diameter variations (leading to non-uniform mass distribution), which probably explains their observation that the first fundamental vibration mode was excited at multiple frequencies (at 0.5 f 1 , f 1 , and at 2 f 1 in our notation).…”

“…By monitoring the current through these bridges, the mechanical resonance (see Figure 9e,f) could be read out externally, which allowed the detection of surface adsorbed molecules down to (sub-)monolayer coverages. [47] For completion, Igaki et al showed that the mass sensitivity of their high-aspect carbon FIBID pillar reached the 10 femtogram range [86], and Hao et al [90] demonstrated the mass sensitivity of their Pt-C FEBID pillar to be 0.4 attograms.…”

“…(b) Buckled Pt-C pillar between an actuator (top) and substrate (bottom). The initial shape was straight as indicated, modified from Hao et al [90]. (c) Pt-C FEBID pillar nanocompression by a flat diamond punch (not shown), modified from Lewis et al [48].…”

“…Arnold et al [47], see Figure 13a, used an electrostatic field to bend the Pt-C FEBID pillars within toward the electrode and calculated the elastic modulus via finite element simulation of the spatially distributed force field. Hao et al [90] is the only reference using Eulerian pillar buckling for modulus determination. Although the method seems simple, as shown in Figure 13b, it is not easy to judge how the top load is fixing the pillar.…”