Elastic Modulus Measurements on Large Diameter Nanowires Using a Nano-Assembled Platform

Abstract

This paper presents atomic force spectroscopy (AFM) results from large diameter nano wires (NWs), which range in radius from 150 nm to 300 nm, within a nano-assembled platform. The nanomechanical platform is constructed by assembling single NWs across pairs o f gold nano-electrodes using dielectrophoresis and contains a short, suspended segment of the NW (in air) between the assembly electrodes. Atomic force microscope (AFM) force spectroscopy measurements are obtained by indenting the NW within this suspended segment and result in deformation of the NW involving a combination of both, bending and nano-indentation modes. This paper demonstrates the measurement tech nique using lithium iron phosphate NWs as a model system and presents a finite element model to extract the Young's modulus from nanomechanical data. The estimated Young's modulus of this material, which is an electrode material system of interest for nextgeneration lithium-ion batteries, was found to be diameter dependent and was observed to range in values between 100 MPa and 575 MPa.

Single nanowire manipulation within dielectrophoretic force fields in the sub-crossover frequency regime

“…Isolation and manipulation of individual 1-D elements from their respective agglomerated precursors, and their integration into functional nanostructures is essential for two reasons: (1) to understand the unique structure-property-performance relationships that emerge in these nanoscopic objects, 1 and (2) to realize functional devices for application areas such as sensing, nanoelectromechanical systems, energy storage, fuel cells and nanoelectronics. [2][3][4][5] One technique for the integration of 1-D elements into nanostructures and nanodevices is their assembly by dielectrophoresis (DEP) [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] on substrates such as silicon. DEP relies on the forces exerted by spatially non-uniform electric fields on polarizable objects to manipulate NWs/NTs, which are suspended either in solvents or in a surfactant stabilized aqueous medium.…”

“…This is because DEP forces are exerted on any object as long as it has a sufficiently higher polarizability with respect to the suspension medium at the excitation frequency. Past reports, which have included contributions from the authors of this article, have demonstrated DEP assembly of material systems such as carbon nanotubes, [5][6][7][8][9] silicon nanowires, [11][12][13] rhodium nanowires, 13 manganese dioxide nanowires, 4 gold nanowires, 16 and lithium iron phosphate nanowires, 17 among others.…”

“…While most earlier reports demonstrated assembly of multiple or bundles of nanowires at the deposition locations, [20][21][22] there have since been many reports on successful demonstration of single particle DEP assembly, though with varying yields. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Some of these single particle assembly methods, particularly ones with higher deposition yields, have employed additional steps/processes beyond DEP manipulation. 11,13,14,23 For instance, ref.…”

Dependence of Young's modulus on the sodium content within the structural tunnels of a one-dimensional Na-ion battery cathode

“…The devices are realized using an on-chip nanofabrication approach, which uses a combination of top-down silicon nanomachining and bottom-up dielectrophoretic (DEP) nanoassembly techniques. This nanoassembly-enabled fabrication approach, which has been presented in detail in our past reports, [38][39][40] involves the following steps. A silicon chip, which measures 4 mm by 6 mm and has an insulating layer of 100 nm thick nitride film on its top-side, serves as the starting substrate.…”