Mikio Naruse

Simultaneous Observation of Millisecond Dynamics in Atomistic Structure, Force and Conductance on the Basis of Transmission Electron Microscopy

High-resolution transmission electron microscopy (HRTEM) has been developed to possess functions of atomic force microscopy and scanning tunneling microscopy. Dynamics of subnano Newton-scale force and conductance were simultaneously observed at intervals of 1/30–1/3840 s during HRTEM imaging of contact, deformation and fracture processes between nanometer-sized tips. The experimental basis of the atomic-scale mechanics of materials was developed on the basis of the present microscopy.

New 300 kV Energy-Filtering Field Emission Electron Microscope

In order to observe high-spatial-resolution elemental images using inelastic electrons, a 300 kV energy-filtering transmission electron microscope with an omega-type energy filter has been developed. Some characteristic features of the new microscope are described. The accelerating voltage dependence of the inelastic images is calculated to confirm that the spatial resolution for the elemental images is improved with an increase in the voltage from 120 kV to 300 kV. It is shown that a single atomic layer of oxygen atoms in Al11O3N9 crystal is well imaged as a bright line with a periodic separation of 2.9 nm al the c-axis. The spatial resolution for the oxygen images is about 0.5 nm, which corresponds well with the theoretical calculation.

Performance of a Monochromator for a 200 kV Analytical Electron Microscope

We have been developing a 200 kV analytical electron microscope, which is equipped with a monochromator [1]. The target performance of the microscope is to achieve an energy resolution of 0.2 eV with a smaller than 2 nm diameter probe on a specimen plane. Though the ultimate energy resolution of 0.14 eV was obtained with our first monochromator, the shape of the beam on the specimen plane was oval [2]. The new monochromator consists of two dodecapole-type Wien-filters (Fig. 1) of 30 mm length and a slit on the symmetric plane of the two filters [2], [3]. The upper (1st) filter and the electro-static round lens at the entrance of the monochromator make an energy-dispersed focus on the slit. The lower (2nd) filter cancels the energy dispersion and makes an achromatic and stigmatic focus at the exit of the monochromator. We obtained the energy dispersion of 19.5 μm/eV on the slit experimentally, which is sufficient to obtain the energy resolution of 0.2 eV using the slit. Figure 2 shows the shape of a 200 keV electron beam on the specimen plane with the new monochromator. It shows that an almost round shaped beam or a better achromatic beam of a 4 nm (FWHM) was obtained. A smaller beam than a 2 nm diameter on the specimen plane at the achromatic condition of the monochromator will be obtained by using a higher excitation condition of the probe forming lens system. We have succeeded in obtaining an energy-dispersed beam on the slit and a stigmatic and achromatic beam at the exit of the monochromator.

Time-Resolved High-Resolution Transmission Electron Microscopy Using a Piezo-Driving Specimen Holder for Atomic-Scale Mechanical Interaction

: Time-resolved high-resolution transmission electron microscopy at a spatial resolution of 0.2 nm and a time resolution of 1/60 sec using a piezo-driving specimen holder is reported here. Various types of atomic processes in mechanical interaction, such as contact, bonding, deformation, and fracture, in nanometer-sized gold crystallites and carbon nanotubes are demonstrated.