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Microgrippers that are able to manipulate nanoobjects reproducibly are key components in 3-D nanomanipulation systems. We present here a monolithic electrothermal microgripper prepared by silicon microfabrication, and demonstrate pick-and-place of an as-grown carbon nanotube from a 2-D array onto a transmission electron microscopy grid, as a first step toward a reliable and precise pick-and-place process for carbon nanotubes.

Current research work on the development of different depth-detection methods for supporting pick-and-place manipulations of carbon nanotubes (CNTs) in a scanning electron microscope (SEM) is presented. A nanorobot station capable of performing this manipulation task in the SEM’s vacuum chamber has been developed, consisting of two cooperating nanorobots. One robot carries an electrothermal microgripper and also performs the coarse approach between microgripper and CNT. The second robot serves as sample holder and realizes the fine positioning of the CNT sample. For a reliable fine approach between microgripper and CNT as well as an intended future automation of handling tasks, depth-detection methods are required in order to precisely measure and align the z-position of microgripper and CNT. Two different methods for z-position estimation are proposed. The depth from focus method uses the focusing information of SEM images whereas the touchdown sensor concept relies on a bimorph piezo bending actuator. The feasibility of both approaches is shown and first experimental results are discussed. Future work has to show how the proposed methods will increase the efficiency of nanorobotic manipulation and how these methods can advance the automation of nanohandling tasks.

We present a high-aspect ratio three-beam electro-thermally actuated gripper made from single-crystalline, highly doped silicon, and compare the performance to a five-electrode electrostatic gripper in terms of actuation and manipulation capabilities. The electrothermal gripper can be configured in a number of different ways, which leads to a high degree of adaptability to various manipulation scenarios. Finally, we consider different options for customising the gripper microcantilevers by add-on nanotips.

Silicon-rich nitride, deposited by LPCVD, is a low stress amorphous material with a high refractive index. After deposition the silicon-rich nitride thin film is annealed at temperatures above 1100 °C to break N H bonds, which have absorption peaks in the wavelength band important for optical telecommunication. However, silicon clustering appears in the thin films when annealing above 1150 °C. Clustering is undesirable in waveguide materials because the localized variations of the refractive index associated with the clusters lead to Raleigh scattering, which can cause significant propagation loss in optical waveguides. This means that the annealing temperature must be high enough to break the N H bonds, but no so high as to produce clusters. Therefore, the process window for an annealing step lies between 1100 and 1150 °C. The chemical composition of amorphous silicon-rich nitride has been investigated by Rutherford back scattering (RBS) and X-ray photoelectron spectroscopy (XPS). The influence of deposition parameters and annealing temperatures on the stoichiometry and the chemical bonds will be discussed. The origin of the clusters has been found to be silicon due to severe silicon out-diffusion from the substrate during annealing at temperatures above 1100 °C.

By using unbalanced magnetron sputtering, TiN/TiAlN multilayers with bilayer lengths from 10 nm to 30 nm and thickness of 3 μm were deposited on steel substrates. The multilayer microstructure was characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy; and the chemical composition by Rutherford backscattering and elastic recoil detection analysis. The mechanical properties were investigated by nanoindentation and stress measurements, where the radius of curvature of the substrate was measured. Tribological properties were obtained by pin-on-disc measurements. Similar hardness values were observed for the multilayers and the single-layer coatings, while large improvements of the wear properties were observed for the multilayers compared to the single-layer coatings. This was connected to a change in wear mechanism, the adhesive wear being significantly reduced in the multilayers.

A nanorobotic manipulation setup for the handling and characterization of carbon nanotubes (CNTs) is presented. The nanorobotic setup can be integrated into a scanning electron microscope (SEM) and various endeffectors may be attached to the manipulator either for CNT handling or characterization. The pick-and-place task is carried out by using an electrothermal actuated microgripper, designed for controlled manipulation of nanotubes. The nanotube is picked up from an array of multiwalled carbon nanotubes (MWCNTs) and transferred to the tip of an atomic force microscope (AFM) probe in order to assemble a high-aspect ratio AFM supertip. Another application of the nanorobotic setup considered in this paper is the nondestructive mechanical characterization of CNTs. A piezoresistive AFM probe is used to bend MWCNTs, while the bending force is measured, in order to estimate the Young's modulus of the investigated MWCNTs.

Current research work on the development of a nanorobot station for the manipulation and characterization of carbon nanotubes is presented. Therefore two nanorobots are cooperating in the vacuum chamber of a scanning electron microscope (SEM). One robot is carrying a nanogripper and is used for the coarse positioning. The second robot serves as sample holder and realizes the fine positioning. In the course of automatic handling tasks, depth-detection within the SEM is required. Two different methods for the z-position estimation of gripper and carbon nanotube are proposed. On the one hand a depth from focus method using real-time processing of noisy SEM images and on the other hand a touchdown sensor concept based on a bimorph piezo bending actuator. Both methods are described in a theoretical framework and are partly verified by experimental tests.

Functional devices can be directly assembled using microgrippers with an in situ electron microscope. Two simple and compact silicon microgripper designs are investigated here. These are operated by electrothermal actuation, and are used to transfer a catalytically grown multi-walled carbon nanofibre from a fixed position on a substrate to the tip of an atomic force microscope cantilever, inside a scanning electron microscope. Scanning of high aspect ratio trenches using the nanofibre supertip shows a significantly better performance than that with standard pyramidal silicon tips. Based on manipulation experiments as well as a simple analysis, we show that shear pulling (lateral movement of the gripper) is far more effective than tensile pulling (vertical movement of gripper) for the mechanical removal of carbon nanotubes from a substrate.

Amorphous silicon rich silicon nitride optical waveguides clad in silica are presented as a high-index contrast platform for high-density integrated optics. Performance of different cross-sectional geometries have been measured and are presented with regards to bending loss and insertion loss. A sample double ring add-drop filter is presented.

The optical nonlinearities of amorphous silicon rich nitride corresponding to χ(3) in a static electric field have been measured by tracking wavelength shifts in the resonances of optical waveguide ring resonators as a function of an applied electrical field. The magnitude of the nonlinearity measured agrees well with expected values.