Controlled manipulation of carbon nanopillars and cantilevers by focused ion beam

Abstract

We explore a novel phenomenon of focused ion beam (FIB) induced bending of carbon nanopillars or cantilever structures. The bending occurs towards the ion beam during scanning. The explanation of this bending has been sought on the basis of a model which considers temperature rise and gradients caused by the impinging ion beam. The process is controllable and reversible, which makes it highly suitable for in situ manipulation to make desired 3D shapes by the piecewise bending of the nanopillars and cantilever structures during their fabrication using electron beam or FIB chemical vapor deposition (EB-CVD or FIB-CVD). Its usefulness in the fabrication of nanosize mechanical components has been demonstrated by making a branch structure from a single cantilever.

Effects of temperature on the ion-induced bending of germanium and silicon nanowires

“…This phenomenon has been demonstrated in a wide variety of structures such as nanotubes [15], microcantilevers and nanowires [16], [17], [13], [12], [18]- [21]. With appropriate tuning of the ion beam parameters, the nanostructures can either be bent away from or towards the incoming ion beam.…”

“…Following their work on C nanopillars and cantilevers, Tripathi et al. put forward a mechanism for IIB towards the beam which was based on thermal expansion inside the target structure during irradiation [21]. Rajput et al have studied metallic cantilevers, Al nanowires and polycrystalline Si nanowires [17], [20], [22].…”

Study of temperature rise during focused Ga ion beam irradiation using nanothermo-probe

“…Ion and electron beam induced local heating [1,2] leads to variety of interesting effects such as bending of nanopillars [3], diffusion of substrate atoms into the nanostructures [4], improvement in the adhesion of thin films on substrates [5][6][7] and focused ion beam lithography for MOSFET devices [8]. Hence the experimental and theoretical estimation of the local temperature rise upon ion/electron beam irradiation is very important to understand all theses effects.…”

Ion-beam-induced bending of freestanding amorphous nanowires: The importance of the substrate material and charging

“…[6][7][8][9][10][11][12][13][14][15][16][17][18] To date, the study of ion-beam-irradiation-assisted bending has been conducted on nanowires of a wide range of materials, including carbon nanotube/nanowires, [6][7][8] Si 3 N 4 , Au/Si 3 N 4 , MoSi 2 cantilevers, [9][10][11] Si, 12 GaAs, 13 ZnO, 14 and Ge. 15 A number of bending behaviours have been observed and different bending mechanisms have been proposed, 7,[12][13][14][15][16][17] taking into consideration parameters such as the kinetic energy, mass, fluence, and incident angle of the ion beam. However, little attention has been given to the possible effect of Coulomb interaction and the role the substrate plays in this.…”

“…However, little attention has been given to the possible effect of Coulomb interaction and the role the substrate plays in this. [6][7][8][9][10][11][12][13][14][15][16][17] In the present work, we explore the effect of the supporting-substrate conductivity and ion-beam scanning strategy on the bending induced by focused-ion-beam irradiation in freestanding amorphous nanowires. We observe the bending of the nanowires towards, away from, and transverse to the ion beam depending on the substrate used and the details of the ion scans.…”