• Microwave processing is one of the attractive fields in recent materials processing. We perform various materials processing using non-equilibrium reaction field induced by microwave and/or ultrasonic irradiation. The topic contains powder metallurgy, nitride coatings, synthesis of new functional materials, fabrication of nanoparticles, etc. Recently we have developed a new TiN coating method using our microwave irradiation equipment operated at a frequency of 2.45 GHz. The method is simple but applicable to various substrates with complex shape. This method can be applied to various nitride coatings and will open a new coating technology in many fields of applications.

The major targets of TiN coatings are for cutting tools, ball bearings, dental implants, die and mold for stamping, and ornaments. The newly developed method makes it possible to perform nitride coatings within a short time using a standard microwave heating equipment. We hope to conduct collaborative research with a willing company for a practical application of these technology.

Nitride semiconductor free-standing substrate production method
https://www.t-technoarch.co.jp/data/anken_en/T14-121.pdf
This invention relates to a technique for producing high-quality nitride semiconductor freestanding substrates at a lower cost. The invention also includes the use of SCAlMgO4 substrates as seed crystals. The dislocation density of nitride semiconductors on this substrate becomes lower. By controlling the crystal polarity, the crystal diameter can be expanded as well as the thickness of the nitride semiconductor.

It is possible to fabricate freestanding nitride semiconductor substrates with lower through-dislocation density than conventional substrates. Furthermore, the cleavage property of ScMgAlO4, which serves as the substrate, facilitates the exfoliation of the nitride semiconductor and reduces the cost of substrate fabrication.

• Usage of ScAlMgO4 as a source substrate.
• Expansion of crystal diameter by using N-polar growth
• When ScAlMgO4 is used as the seed crystal and AlN is formed as the surface protective layer of this crystal, the surface shall be further nitrided after oxidation of the surface.
• The main surface of the seed crystal shall be inclined 0.4 to 1.2° from the c-plane.

This invention is to provide high-quality, low-cost free-standing nitride semiconductor substrates for optical devices such as light-emitting diodes and lasers, and transistors operated under high power, high voltage, and high frequency. Companies are expected to verify the commercialization of the product.

• 1. Development of Distributed Feedback (DFB) Laser Diodes (LD) widely used in optical communications systems realizing a highly information-based society. This LD increases the transmission capacity by 25,000 times per fiber which means the bit rate of 10Tb/s.
• 2. Nitride semiconductors famous for blue light emitting diodes.
• (a) Proposal of InGaAlN system considering device applications in 1989
• (b) Success in growth of single crystalline InGaN by metalorganic vapor phase epitaxy (MOVPE) in 1989
• (c) Prediction of band-gap energy (Eg) of InN much smaller than the values reported in 1980s and its 　 experimental confirmation in 2002
• (d) Observation of photoluminescence from InGaN in 1991
• (e) Prediction of phase separation in InGaAlN in 1997

DFB-LD: Fabrication of periodic structure with submicron scale, Epitaxial growth of semiconductor films on the substrate with fine structures, LD fabrication process, device evaluation, and device simulation

Nitride Semiconductors: MOVPE growth, N-polar growth, Evaluation of semiconductor materials, Fabrication of light-emitting devices, solar cells, and high-power transistors

• Conventional X-ray imaging methods that rely on X-ray attenuation cannot generate clear contrast in the observation of low-density materials such as polymers consisting of low-Z elements. However, the sensitivity to the materials can be improved drastically by X-ray phase imaging that detects X-ray refraction caused by the materials. X-ray Talbot or Talbot-Lau interferometry consisting of X-ray transmission gratings is now constructed in laboratories for X-ray phase imaging. X-ray phase tomography is also realized, enabling high-sensitive three-dimensional observation.
• X-ray phase imaging can be utilized for X-ray non-destructive testing of industrial products and baggage that cannot be checked conventionally.

We aim at appending a phase-contrast mode to micro-CT apparatuses and developing screening apparatuses in production lines.

• The emergence of stress corrosion cracking is one of the most important issues from the viewpoint of aging management and maintenance of nuclear power plants. There is a large discrepancy between stress corrosion cracking and other cracks such as fatigue cracks from the viewpoint of nondestructive testing and evaluations, which requires suitable specimens containing stress corrosion cracking for the development of nondestructive testing and evaluation techniques and also for personnel training. However, artificially introducing stress corrosion cracking needs large cost and long time. Furthermore, several studies have pointed out that such articial stress corrosion cracking is not always similar to natural ones. On the basis of the background above, we develop a method to fabricate "imitative" stress corrosion cracking specimens using diffusion bonding.

The method enables one to introduce a region whose response is almost identical to actual stress corrosion cracking from the viewpoint of nondestructive testing. Whereas the dimension of the region is accurately controllable, the method requires much less cost and time comparing the conventional ones using corrosive environment. Patent is already applied for.

Colorful TiO2 Particle
https://www.t-technoarch.co.jp/data/anken_en/T19-849.pdf

Transition metal compounds are known to exhibit a wide variety of colors. Until now, it has been possible to color white titanium oxide by doping with transition metal ions, but it is difficult to avoid biotoxicity derived from transition metals.

• In the present invention, titanium oxide inorganic pigments that do not contain transition metals and have various colors such as white, yellow, red, gray, green, purple, black, and skin color have been realized.

New applications of titanium oxide pigments are expected in the cosmetics field, where biotoxicity is an issue.

• Highly-sensitive NMR technique has been developed by manipulation polarization of nuclear spins via control of transport characteristics in GaAs and InSb quantum structures. This highly-sensitive NMR can be applied to two-dimensional and nanostructures. Furthermore, ideal gate controllability has been demonstrated in InSb quantum structures with Al2 O3 dielectrics. More importantly, the concept of generalized coherence time was introduced, where noise characteristics felt by nuclear spins can be measured including their frequency dependence. This concept will bring about a change in all nuclear-spin related measurements.

Next generation InSb devices based on good gate controllability. Various nuclear-spin based measurements and NMR utilizing the concept of generalized coherence time. Highly-sensitive NMR is now important for fundamental physics studies. In the future, it will contribute to quantum information processing.

We have developed a technique for quantitative analysis of microstructures (e.g., dislocations and irradiation defect aggregates) of activated and nuclear-burned specimens in the context of the Week Beam Scanning Transmission Electron Microscope (WB-STEM) method, which boasts extremely high measurement accuracy as a quantitative analysis method for lattice defects.
In combination with a dedicated heated sample holder with fully automated temperature measurement and current control in a cartridge-type heating furnace, changes in dislocation microstructure can be dynamically measured in-situ along with a highly reliable temperature history.

Conventional TEM methods require expertise in reciprocal space and dislocation theory, but our WB-STEM method is equipped with automatic analysis software for film thickness measurement and dislocation loop feature extraction, making it possible to analyze irradiation defects easily and precisely.

• Since its design, the WB-STEM method has been developed for implementation and on-site repair in radiation controlled areas where nuclear materials are handled, with special aperture and diffraction disc selection equipment, control and analysis software.
• WB-STEM accepts irradiation defect analysis of activated specimens from all over the world, including RPV monitoring specimens from European reactors and neutron-irradiated materials from US research reactors.
• It is also used to analyze the properties of iron-containing nuclear fuel simulated debris in decommissioning projects.

We support research organizations that currently use transmission electron microscopy to observe microstructures to introduce the WB-STEM method by special modification. We will instruct researchers who have no experience using transmission electron microscopy in the procedure for dislocation analysis.

• The emergence of stress corrosion cracking is one of the most important issues from the viewpoint of aging management and maintenance of nuclear power plants. There is a large discrepancy between stress corrosion cracking and other cracks such as fatigue cracks from the viewpoint of nondestructive testing and evaluations, which requires suitable specimens containing stress corrosion cracking for the development of nondestructive testing and evaluation techniques and also for personnel training. However, artificially introducing stress corrosion cracking needs large cost and long time. Furthermore, several studies have pointed out that such articial stress corrosion cracking is not always similar to natural ones. On the basis of the background above, we develop a method to fabricate "imitative" stress corrosion cracking specimens using diffusion bonding.

The method enables one to introduce a region whose response is almost identical to actual stress corrosion cracking from the viewpoint of nondestructive testing. Whereas the dimension of the region is accurately controllable, the method requires much less cost and time comparing the conventional ones using corrosive environment. Patent is already applied for.