Platinum Composite Nanowires For Ultrasensitive Mass Detection

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) x 10(2) GPa to (4.7 +/- 0.2) x 10(2) GPa, dependent on the wire size. A mass responsivity of 2.1 x 10(21) 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. Published by AIP Publishing.