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Exploring nanoworld toward frontiers;
imaging, measuring, assembling atoms

*This Lab. is not accepting new student.

TOMITORI Lab.
Professor: TOMITORI Masahiko

E-mail:
[Research areas]Surface science, imaging, nano-mechanics
[Keywords]Scanning probe microscopy, electron spectroscopic microscopy, nanomaterial, contacts, instrumentation

Skills and background we are looking for in prospective students 

Curiosity about science, technology, and nature. Attitude to eagerly try to catch them through experiments and research, and organize them to understand. Furthermore, it is perfect if you understand fundamental physics, chemistry, engineering, as well as electronics, machining, mechatronics, and vacuum technologies.

What you can expect to learn in this laboratory

Profound insight to phenomena in nature as well as science and technology on the basis of concept of atoms and molecules. Scientific literacy. Basics of nano-science and technology, solid state physics, surface science, and their applications. Basic knowledge on materials such as metals, semiconductors, oxides, and molecules. Nanoscale imaging technology, and skills of instrumentation to measure the properties of materials, as well as instrument design, production, and repair. Fabrication of thin films and nanostructures in ultrahigh vacuum.

【Job category of graduates】
Researchers and engineers in material research and manufacture in the related institutions and companies

Research outline

We aim at the new frontier in surface science on a nanoscale through development of novel instrumentation based on scanning probe microscopy/spectroscopy (SPM/SPS) techniques; so-called nanoprobe technology. SPM can depict atom-resolved images of sample surfaces using an atomically sharpened tip, which is scanned over the surfaces in a close proximity while maintaining constant tunneling current (in scanning tunneling microscopy (STM)) or force (in atomic force microscopy (AFM)) between the tip and the surfaces. Quantum mechanical behaviors can be interestingly revealed by the methods. Our targets cover exotic materials such as semiconductors, oxides, atoms and molecules adsorbed on their surfaces, and nanoscale and atomic scale point contacts and welding towards new nano-mechanical electronic devices and chemical reactions. We also develop the novel methods to evaluate and fabricate the atomically sharpened tips, which are the heart of the SPM techniques to explore the nanoworld, by combining with other microscopic and spectroscopic techniques.

1. Development of Tip Science (nanoprobe technology) to visualize the nanoworld with atomic resolution.
The STM and AFM setups can be operated in ultrahigh vacuum (UHV, in the range of 10-11 Torr or better), air (or gas-, humidity-controlled), and liquid (water), which are custom-developed. The probes (tips) are in-situ characterized using field ion microscope (FIM) and field emission microscope (FEM), and modified to be sharpened and stabilized under high electric field at high temperatures, or mechanically contact in well-controlled ways supported by recipes established in surface science.

2. Nanoscale spectroscopic surface analysis of metals, semiconductors, and oxides, with deposited heterogeneous layers and adsorbed molecules, in reactions, melting, decomposition, dissolution, and surface diffusion to form novel exotic nanomaterials.

3. Nano-mechanics to study the interactions between the materials on an atomic scale; the chemical and electrostatic forces are investigated with mechanical energy transfer toward assembling nanostructures.

Key publications

  1. Toyoko Arai, Ryo Inamura, Daiki Kura, and Masahiko Tomitori: “Energy dissipation unveils atomic displacement in the noncontact atomic force microscopy imaging of Si(111)-(7×7)”, Physical Review B 97 (2018) 115428.
  2. Toyoko Arai, Kohei Sato, Asuka Iida, and Masahiko Tomitori: “Quasi-stabilized hydration layers on muscovite mica under a thin water film grown from humid air”, Scientific Reports 7 (2017) 4054.
  3. Makoto Nogami, Akira Sasahara, Toyoko Arai, and Masahiko Tomitori: “Atomic-scale electric capacitive change detected with a charge amplifier installed in a non-contact atomic force microscope”, Applied Physics Express 9 (2016) 046601.

Equipment

Ultrahigh vacuum scanning tunneling microscope (STM)
Ultrahigh vacuum non-contact atomic force microscope (AFM)
Environmental controlled non-contact atomic force microscope
Scanning Auger electron spectroscopy microscope

Teaching policy

Communications are very important even in scientific societies, as well as basic and specialized scientific knowledge and technical skills are. We should acquire the abilities to clearly and plainly show and tell what we think to others, and also to learn what others think and tell to us, and furthermore, to sincerely issue questions to the others, which may reach to the core of them. Those attitudes can lead us to achieve the creative and innovative works toward realization of our dreams.

[Website] URL:http://www.jaist.ac.jp/ms/labs/kkk/Tlab/Tlab_home-j.html

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