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Surface Physics and Characterization Group

Surface Physics and Characterization Group aims at explication of the physical development used for state-of-the-art technology. The process of the surface reaction and the change of physical properties formed by a reaction are considered in physico-chemistry. If it's a project study of NIMS to run after the target which should be used for industry and near view-like, the goal of our group is to elucidate the physical development used by the project.

What's new?

Tomoya Iwasawa received JVSS Student Award!

Tomoya Iwasawa, NIMS Junior Researcher/Graduate student of University of Tsukuba, has received Student Award from the Japan Society of Vacuum and Surface Science (JVSS).
This award was given to his excellent poster presentation titled "Observation of behavior of deuterium permeated through stainless steel" at 2018 Symposium of JVSS (Oct. 2018, in Kobe, Japan).
 
The award ceremony was held in May 2019 at University of Tokyo.

"At the award ceremony.  The 4th person from the left is Mr. Iwasawa." Image

At the award ceremony. The 4th person from the left is Mr. Iwasawa.


"At Interface Science Laboratories, NIMS." Image

At Interface Science Laboratories, NIMS.




1 Position Available (Postdoctoral Researcher)

Job Summary: 
Hydrogen measurement with operando- hydrogen-microscope and analysis of the data.
Design, arrangement and operation of ultra-high vacuum equipment for the microscope.

Term:
1 year (Possibly up to 3 years) 

For more information, please check here.


NIMS Movie Introducing Our Research

On NIMS official website, you can watch the movie produced by NIMS.
Here is the one titled "Visualize the distribution of hydrogen in materials - Development of one and only microscope -" (in Japanese).  Dr. Itakura and Dr. Miyauchi are introducing the outline of research. 

*The movie is protected under copyright low.


Other information

 Please see "Bulletin Board" down below.


Specialized Research Field

The research subjects progressing at present are as below:
 
  • Study phenomena which occur at surfaces and interfaces, using the methods like electron spectroscopy, surface stress, and measurement of trace elements emission, etc.
  • Develop sensors of gas molecules or protein molecules from the stresses of reactive thin films as adsorbent of the target molecules.
  • Visualize hydrogen outgassing from a metal surface, and elucidate the behavior of hydrogen in materials, so that we can contribute to “hydrogen energy society”.


Research Topics: Development of Operando Hydrogen Microscope

Hydrogen in metals causes hydrogen embrittlement, which is the process of various metals to become brittle and fracture. We have been investigating hydrogen behavior in metal alloys by observing two-dimensional hydrogen distribution on metal surface using a method of DIET (Desorption Induced by Electronic Transition), membrane sample, and hydrogen supplying system from backside of the sample.


■What's Operando Hydrogen Microscope?

It is a microscope to visualize hydrogen using DIET (Desorption Induced by Electronic Transition) method. It picks up week and small signals with integration measurement for a long time.

We have made that possible by using a certain hydrogen supply type and pulse counting detection system. It has no damage on a sample, and it gets hydrogen pictures in real time measurement (Fing.1, 2). 

Also, it detects time dependence of hydrogen desorption, temperature dependence, hydrogen gas pressure dependence (hydrogen supplying pressure to the backside of a sample), and other gas dependence (humidity, oxygen, etc.).
 

* Sometimes, the DIET phenomenon is called "ESD; electron stimulated desorption". ESD is included in DIET.


"Fig.1. Schematic image of SEM and DIET experiment" Image

Fig.1. Schematic image of SEM and DIET experiment


"Fig.2. Experimental set up of the two dimensional detection system of Hydrogen permeation" Image

Fig.2. Experimental set up of the two dimensional detection system of Hydrogen permeation




■Hydrogen Map of Permeated Hydrogen on Stainless Steel (SUS304).

Fig. 3 shows the SEM picture and H map (DIET image) on SUS 304 steel at 473K. In SEM pictures, austenite grains in the order of 100 μm size are confirmed. Stripes in a grain suggest martensite dislocations, and such grains look dark. Depending on the time, the relationship of hydrogen map and the SEM image are varied. 

"Fig.3. (a) SEM picture. White circles are on triple-points and multiple-points of grain boundary. (b) DIET hydrogen image after 3 h from hydrogen supply to the backside of sample. White circles are on the same position with (a)." Image

Fig.3. (a) SEM picture. White circles are on triple-points and multiple-points of grain boundary. (b) DIET hydrogen image after 3 h from hydrogen supply to the backside of sample. White circles are on the same position with (a).




We focused on the initial stage of hydrogen permeation.

Fig. 3 shows the DIET map at 3 h after the initial backside exposure. There are several sites of relatively high hydrogen concentration in this time period, marked by circles in the figure.
According to the one-dimensional diffusion equation, the permeation time of hydrogen through a 100 μm austenite membrane is calculated to be more than 4 h. This indicates that the rapid permeation of hydrogen does not take a path through austenite.

Considering the permeation path by comparing the DIET map with the SEM image, we found that the areas of high hydrogen concentration were the areas with high density of grain boundaries which were gathered or crossed.  

"Fig.4. (a) SEM picture and (b) H distribution on the same area with (a). Ion counts of each position are the sum of 550 pictures measured for 55 h. Handwritten lines are added on the grain boundary to make the image easier to see." Image

Fig.4. (a) SEM picture and (b) H distribution on the same area with (a). Ion counts of each position are the sum of 550 pictures measured for 55 h. Handwritten lines are added on the grain boundary to make the image easier to see.




Let's compare the SEM and DIET image, focusing on the bright grains in the SEM (Fig. 4 (a) and (b)).

The grain shape in the SEM image corresponded with a high yield shape of hydrogen. In other words, it's making good agreement with hydrogen permeation.
The hydrogen diffusion constant is larger in the striped part in gray grains than that in the bright grains; that is larger in the martensite structure than in the austenite structure.

Howeber, some of the striped grains do not show a high concentration of hydrogen. We considered the paths of hydrogen through the membrane (sample thickness, 100μm; grain size, 100–150μm). 

Related Image


 We assumed 4 types of hydrogen path through the sample membrane: (a) hydrogen diffusing through a single striped grain (austenite grain with martensite dislocations), (b) hydrogen diffusing through a single austenite grain, (c) hydrogen diffusing from a striped grain to an austenite grain, and (d) hydrogen diffuse through grain boundaries,  (Fig.5).

In addition, the flow rate of hydrogen should differ according to the crystallographic orientation because each crystallographic face has an intrinsic atomic density. 

By using electron backscatter diffraction (EBSD) patterns as a reference, we have found instances where more than two grains existed in what appeared as a single grain in a SEM image. EBSD can determine the structure of the grains and the orientation of the crystals.
Also, the orientation of the adjacent grains is very important when considering the structure of the grain boundary, which is expected to influence hydrogen permeation through the grain boundary.

In the future, we intend to compare the DIET mapping of hydrogen with structural analysis including EBSD measurements.


Research Topics: Gas Sensing and Molecule Sensing

■Hydrogen Gas Sensing with Pd Alloy.

In preparation (Patent pending 2017-155808,Patent pending 2019-40136, Japan)


■Protein Sensing with Molecule Imprinted Polymer.

In preparation.


Research Topics: From a research sample to practical devices -Evolution of characterization

"Multi-dimensional mapping of GaN:Eu red LED" Image

Multi-dimensional mapping of GaN:Eu red LED


Photoluminescence is the first screening technique for luminescent semiconductors. Despite that, the actual opto-electronic devices are operated with charges (current) rather than light. 
Recently, we developed a multi-dimensional mapping technique for light emitting diodes (LED). The mapping that adopts pulse-driven frequency as an axis revealed a nanoscale luminescence mechanism in GaN:Eu LED (a next-generation GaN-based red LED: Produced by Osaka University), and clarified interactions between emission centers and injection charges, which were different from interactions in the photoluminescence.


Bulletin Board

News and Information of Research Center

Surface Physics and Characterization Group belongs to Research Center for Advanced Measurement and Characterization (RCAMC) of NIMS.
Please click here for the latest information of RCAMC.


Research Outline in NIMS Newsletter

The outline of Dr. Itakura’s research was introduced in NIMS NOW, the newsletter of NIMS.
You can access the international version article via NIMS website.

NIMS NOW International Vol. 16, No.3, Research Highlight4
Title: "Identifying hydrogen pathways using a microscope capable of measuring diffused hydrogen"


Report of Workshop 2016

A workshop “Solution to quenching problems of nano opto-electronic materials in international framework” was held in Kyoto University on August 19th, 2016. For more details, please come to the workshop homepage.


Recent Publications

The list of recent papers and books. The other publications can be checked with the Related Link "NIMS Researchers Database" at the bottom of the list or "Group Member" at the top of this page.

2019
  • Naoya Miyauchi, Tomoya Iwasawa, Yoshiharu Murase, Shoji Takagi, Akiko N. Itakura, “Observation of Metal Surface by Operando Hydrogen Microscope” Vacuum and Surface Science 62 [1] (2019) 27-32 10.1380/vss.62.27

2018
  • A. N. Itakura, M. Tosa, T. Yakabe, N. Miyauchi, A. Kasahara, T. Miyata, T. Shindo, “Low Outgas Surface Treatment of Stainless Steel 316L Using Segregated Chromium Oxide Layer” Vacuum and Surface Science 61 [10] (2018) 675-680 10.1380/vss.61.675
  • Masaya Toda, Koji Miyake, Li-Qiang Chu, Marjan Zakerin, Renate Förch, Rüdiger Berger, Akiko N. Itakura, “Young's modulus of plasma-polymerized allylamine films using micromechanical cantilever sensor and laser-based surface acoustic wave techniques” Plasma Processes and Polymers 15 [9] (2018) 1800083 10.1002/ppap.201800083
  •  N. Miyauchi, K. Hirata, Y. Murase, H. A. Sakaue, T. Yakabe, A. N. Itakura, T. Gotoh, Shoji Takagi, “2D Mapping of Hydrogen Permeation from a Stainless Steel Membrane” SCRIPTA MATERIALIA 144 (2018) 69-73 10.1016/j.scriptamat.2017.09.026
  • A. N. Itakura, N. Miyauchi, et al., Compendium of Surface and Interface Analysis, Springer (2018)

2017
  • F. Lu, T. Takaya, K. Iwata, I. Kawamura, A. Saeki, M. Ishii, K. Nagura, T. Nakanishi, “A Guide to Design Functional Molecular Liquids with Tailorable Properties using Pyrene-Fluorescence as a Probe” SCIENTIFIC REPORTS 7 (2017) 3416-1-3416-12 10.1038/s41598-017-03584-1
  • A. N. Itakura, N. Miyauchi, Y. Murase, S. Takagi, “Development of Operand Hydrogen Microscope”(in Japanese) The Piping Engineering 59 [13] (2017) 14-18
  • M. Kubo, E. Nango, K. Tono, T. Kimura, S. Owada, C. Song, F. Mafune, K. Miyajima, Y. Takeda, J. Kohno, N. Miyauchi, T. Nakane, T. Tanaka, T. Nomura, J. Davidsson, R. Tanaka, M. Murata, T. Kameshima, T. Hatsui, Y. Joti, R. Neutze, M. Yabashi, S. Iwata, “Nanosecond pump-probe device for time-resolved serial femtosecond crystallography developed at SACLA”JOURNAL OF SYNCHROTRON RADIATION 24 (2017) 1086-1091 10.1107/s160057751701030x
  • F. Mafune, Y. Takeda, J. Kohno, K. Tono, K. Miyajima, N. Miyauchi,“Reduction of Sample Consumption by Factor of Ten Using Droplet Injector for Serial Femtosecond Crystallography”(in Japanese) JOURNAL OF JAPAN LASER PROCESSING SOCIETY 24 [2] (2017) 51-55
  • A. N. Itakura, The Report on Topical Meeting of the Vacuum Society of Japan in June 2017 “Low Temperature Science and Vacuum Science” Journal of the Vacuum Society of Japan 60 [10] (2017) 410-411 10.3131/jvsj2.60.410
  • A. N. Itakura, “The Future Plan of Gender Equality Promotion in JPS” (in Japanese) Butsuri 72 [6] (2017) 383-383 https://doi.org/10.11316/butsuri.72.6_383

2016
  • M. Ishii, “Probe of "non-luminescence" processes” (in Japanese) OYO BUTURI. 85 [3] (2016) 223-227
  • M. Paven, R. Fuchs, T. Yakabe, D. Vollmer, M. Kappl, A. N. Itakura, H-J B. Mechanical, “Properties of Highly Porous Super Liquid-repellent Surfaces” ADVANCED FUNCTIONAL MATERIALS 26 [27] (2016) 4914-4922 10.1002/adfm.201600627
  • M. Ishii, A. Koizumi, and Y. Fujiwara, “Dimerization of emission centers in Eu-doped GaN red light emitting diode: Cooperative charge capturing using valence states coupling” Journal of Physics: Condensed Matter 29, 025702 (2017) doi:10.1088/0953-8984/29/2/025702
  • M. Ishii, A. Koizumi, Y. Fujiwara, “Trapping of injection charges in emission centers of GaN:Eu red LED characterized with 1/f noise involved in forward current” Jpn. J. Appl. Phys. 55[1] (2016) 015801-1 DOI:10.7567/JJAP.55.015801
  • A. N. Itakura, “The future of the Gender Equality Promotion in JPS” Butsuri 71 [4] (2016) 203-203 https://doi.org/10.11316/butsuri.71.4_203

2015
  • Y. Kamon, Y. Kitayama, A. N. Itakura, K. Fukazawa, K. Ishihara, T. Takeuchi, “Synthesis of grafted phosphorylcholine polymer layers as specific recognition ligands for C-reactive protein focused on grafting density and thickness to achieve highly sensitive detection” Phys. Chem. Chem. Phys. 17[15] (2015) 9951-9958 DOI:10.1039/c5cp00469a
  • A. N. Itakura, “Vacuum Components and Movable Mechanism”(in Japanese) JOURNAL OF THE VACUUM SOCIETY OF JAPAN 58[8] (2015) 282-291 10.3131/jvsj2.58.282
  • N. Miyauchi, S. Suzuki, S. Takagi, T. Gotoh, Y. Murase, A. N. Itakura, “Electron Stimulated Desorption Measurement of Permeated Hydrogen through Stainless Steel Membrane”(in Japanese) JOURNAL OF THE VACUUM SOCIETY OF JAPAN 58[10] (2015) 387-391 10.3131/jvsj2.58.387
  • A. N. Itakura,“曇らない鏡の秘密 他 (The secret of non-fogging mirror, etc.)” すごいぞ ! 身のまわりの表面科学 (ブルーバックス, paperback) (in Japanese) (2015) 12-16
  • M. Ishii, A. Koizumi, Y. Fujiwara, “Nanoscale determinant to brighten up GaN:Eu red LED: Local potential of Eu-defect complexes” J. Appl. Phys. 117[15] (2015) 155307-1 DOI:10.1063/1.4918662
  • M. Ishii, S. Fuchi, Y. Takeda, “Interaction of Nd dopants with broadband emission centers in Bi2O3?B2O3 glass: Local energy balance and its influence on optical properties” J. Phys.-Condes. Matter 27[39] (2015) 395402-1 DOI:10.1088/0953-8984/27/39/395402
  • M. Ishii, A. Koizumi, Y. Fujiwara, “Three-dimensional spectrum mapping of bright emission centers: investigating the brightness-limiting process in Eu-doped GaN red light emitting diodes” Appl. Phys. Lett. 107[8] (2015) 082106-1 DOI:10.1063/1.4929531


Group Leader

Group Member

"Tomoya IWASAWA (Graduate School, University of Tsukuba, M2)" Image

Tomoya IWASAWA (Graduate School, University of Tsukuba, M2)


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Surface Physics and Characterization Group
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