Methods and technologies / Synthesis and processing | Research Center for Electronic and Optical Materials

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Methods and technologies
Synthesis and processing

The technologies used at this center can be broadly divided into synthesis/manufacturing technology and evaluation analysis technology.
This page specifically focuses on Synthesis and processing methods. Method for Characterization and measurements is at 【another page 】.

There is also a wide range of Synthesis and processing technologies. First, it is a means of obtaining the desired material by reacting or melting substances at high temperatures, using a so-called "furnace. " On the other hand, it is a means of synthesizing materials at relatively low temperatures, that is, using chemical methods that can be imaged from beakers or flasks. It provides a means of synthesizing substances from liquids such as aqueous solutions. There are also processes that use liquids and do not involve a dissolution step. An example of this is the process of dispersing powder into a liquid. Dispersion processes are of great importance in materials synthesis.

Another method is to synthesize materials by depositing vaporized raw materials as solids on a substrate. This process of precipitating a solid phase from a gas phase is often used for high-purity synthesis in a vacuum environment. Furthermore, this center will utilize shape forming technology such as microfabrication technology for device formation.
We also have equipment available for use by outside organizations. If you are interested, please inquire.

【Characterization and measurements】 page

Solid and melt processes / high temperature processes
We will introduce manufacturing processes that use high temperatures, such as solid phase reactions and melt processes, at this center.

Bulk single crystal growth

It is a process that produces large single crystals from melted liquid at high temperatures.

Production of large, high-quality single crystals for optical applications using the pulling method

Group in charge
Optical Single Crystals Group
SHIMAMURA, Kiyoshi VILLORA, Garcia YUAN, Dongsheng

A CTAS piezoelectric single crystal grown via the Czochralski method. The transparent, pale yellow crystal on a ruler expands fan like to about ninety millimeters in length, demonstrating successful large scale growth. Color variations of LiREF4 crystals. Five crystals are aligned by a ruler. Colors shift based on dopants: transparent (Tb), yellow (Dy), red (Ho), pale pink (Er), and transparent (Yb), illustrating optical property control.

Single crystal growth using Bridgman method etc

Group in charge
Optical Single Crystals Group
NAKAMURA, Masaru

A single crystal grown via the Bridgman method. It has a bullet-like shape with a mirror-like silvery luster. About 4cm long. The uniform reflective surface indicates a highly ordered internal structure.

Sintering

This is the process of creating ceramics by densifying powder at high temperatures.

Fabrication of transparent ceramics using sintering technology

Group in charge
Optical Ceramics Group
SUZUKI, Tohru

Group in charge
Polycrystalline Optical Material Group
MORITA, Koji

Transparent ceramics. Left: spinel disc showing high clarity. Right: SEM cross-section of an alumina layer on a spinel matrix at a 1µm scale, revealing the fine polycrystalline structure at the interface.

High temperature gas reaction

This is a synthesis method that involves reacting a solid at high temperature with a gas. A typical example is nitride synthesis using ammonia.

Synthesis of nitrides and oxynitrides through high-temperature reactions

Group in charge
Advanced Phosphor Group
TAKEDA, Takashi

Group in charge
Electro-ceramics Group
SUEHIRO, Takayuki

Group in charge
Amorphous Material Group
SEGAWA, Hiroyo

Nitride morphologies. Left: one micrometer scale, dense spherical particles. Right: ten micrometer scale, intersecting smooth fibers. These SEM images show the ability to synthesize the same material in particulate and fibrous forms.

We would like to introduce the liquid phase process at this center.

Colloid process

This is a process for controlling the behavior of fine particles dispersed in a liquid to bring out material properties.

Ceramic particle orientation control using field

Group in charge
Optical Ceramics Group
SUZUKI, Tohru

Magnetic ceramic orientation. Top: apparatus and conductivity graph. Bottom: transmittance graph showing aligned samples have higher clarity than random ones. Photos of NIMS text seen through samples confirm the effect.

Production of photonic colloid sheets from suspensions

Group in charge
Nanophotonics Group
FUDOUZI, Hiroshi

Photonic colloidal sheets. Left: precision coating system with a zero point five millimeter scale inset showing a green color. Right: large sheet with a vivid green to blue structural color gradient, demonstrating high quality uniform film.

Precipitation from solution

Solid-phase materials are synthesized by precipitating raw materials dissolved in a solvent.

Precipitation of nanoparticles with controlled particle shape from solution

Group in charge
Electro-ceramics Group
SAITO, Noriko

Zinc oxide particles and gas sensing. Left: microscope image of pyramidal particles. Right: graph of resistivity in ohms. 0.5 percent gold-loaded sample shows higher sensitivity to isoprene gas.

Hydrothermal synthesis method: Crystal precipitation from aqueous solution in critical state

Group in charge
Optical Ceramics Group
NAKANE, Takayuki

Sol-gel method

Group in charge
Amorphous Material Group
SEGAWA, Hiroyo HAYASE, Gen

Electrochemical synthesis method

A synthesis method that induces chemical reactions and mass transport by applying an electric field to the interface between a solution and a solid.

Formation of film by anodic oxidation of metal

Group in charge
Amorphous Material Group
SEGAWA, Hiroyo

Coloration of anodic alumina films. 6 plates show a color transition from gray to yellow. This structural color is achieved by precisely controlling film thickness at the nanoscale to create light interference.

We will introduce vapor phase growth at this center.

Molecular beam epitaxy (MBE)

This is a process in which raw materials are vaporized in a vacuum and then deposited and crystallized on a wafer.

Formation of quantum dots and quantum wells

Group in charge
Semiconductor Epitaxial Structures Group
MANO, Takaaki OHTAKE, Akihiro KAWAZU, Takuya

Quantum dots via droplet epitaxy. Left: apparatus and entangled photon source concept. Right: 200nm micrographs and emission graphs of GaAs and InAs dots (600 to 1600nm), demonstrating optical control.

Crystal growth of nitride semiconductors

Group in charge
Amorphous Material Group
OGAKI, Takeshi

Chemical vapor deposition (CVD)

This is a process in which raw material molecules carried by a gas flow react on the substrate surface and precipitate and crystallize.

Formation of semiconductor thin film by vapor phase growth

Group in charge
Semiconductor Defect Design Group
TERAJI, TokuyukiWATANABE, Kenji

Group in charge
Ultra-wide Bandgap Semiconductors Group
KOIZUMI, SatoshiLIAO, Meiyong

Diamond thin-film growth and devices. Center: growth equipment. Arrows point to a blue-white pn junction, sensors, and an FET. It also highlights heterodevices with ultra-wide bandgap semiconductors like Gallium Oxide.

Hydride vapor phase epitaxy (HVPE)

This is a crystal growth method in which raw metal is transported onto a substrate as chloride gas and crystals are deposited on the substrate.

Group in charge
Ultra-wide Bandgap Semiconductors Group
OSHIMA, Yuichi

Gallium oxide growth. Diagram shows the system setup and a graph of growth rate in micrometers per hour. Bottom: 150 micrometer thick crystal and 5 micrometer hexagonal pillars.

Pulsed laser deposition (PLD)

This is a thin film growth process in which raw materials evaporated by laser pulse irradiation are deposited and crystallized on a substrate wafer.

Formation of semiconductor thin films and dielectric thin films by PLD method

Group in charge
Electro-ceramics Group
ADACHI, YutakaSHIMIZU, TakaoOHSAWA, Takeo

Group in charge
Nano Electronics Device Materials Group
NAGATA, Takahiro

Atomic level control. Left: three nanometer model of a lanthanum aluminate layer on a substrate. Right: one nanometer atomic resolution STEM cross section showing a neat lattice where two materials meet at a sharp interface.

sputtering deposition

Raw materials vaporized using plasma are deposited on a wafer to grow crystals and synthesize thin film crystals.

Formation of semiconductor thin films and dielectric thin films by sputtering method

Group in charge
Electro-ceramics Group
SHIMIZU, TakaoOHSAWA, Takeo

Group in charge
Nano Electronics Device Materials Group
NAGATA, Takahiro

Fabrication processes used in this center

Lithography

It is a process in which fine structures are formed on the surface of a wafer or thin film using pattern formation on a resist film using electron beams or light.

Formation of metamaterials by lithography

Group in charge
Nanophotonics Group
IWANAGA, Masanobu

Group in charge
Semiconductor Epitaxial Structures Group
MIYAZAKI, Hideki

Next-gen metamaterial sensor. Top: gold/quantum well structure. Bottom: electric field simulation, 1µm scale SEM image, and a 5mm packaged device. It shows the leap from microscopic engineering to a practical sensor.

Formation of waveguide type nonlinear optical element by lithography

Group in charge
Quantum Photonics Group
KURIMURA, Sunao

Phase matching and photon pair generation. Top: periodic waveguide. Bottom table: Type zero has a constant d three three of twenty five and efficiency of one. Types one and two have constants of five and efficiency of one twenty fifth.

Etching

This method uses acid/alkaline solutions, plasma, etc. to remove the sample surface by dissolving or evaporating it and giving it the desired shape.

Fabricating metamaterials using lithography

Group in charge
Ultra-wide Bandgap Semiconductors Group
OSHIMA, Takayoshi

Group in charge
Nanophotonics Group
IWANAGA, Masanobu

Non-plasma fabrication. Left SEM: selective growth and etching of fins and trenches. Right: a fin-type transistor at a 50 micrometer scale showing terminals.

Strong magnetic field application

By applying a magnetic field to powder, etc., particle aggregation and orientation are controlled.

Particle motion control using magnetic fields

Group in charge
Optical Ceramics Group
HIROTA, NoriyukiSUZUKI, Tohru

Real-time magnetic particle alignment. Fine black particles in a liquid form vertical needle-like chains. This shows precise orientation control, a key process for developing high-performance ceramics.
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