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

CTAS piezoelectric single crystal grown via Czochralski method. A transparent, pale yellow crystal on a ruler expands fan-like to ~90 mm, proving stable large-scale growth. Color variations of LiREF4 crystals. Five crystals aligned by a ruler. Colors: Tb (clear), Dy (yellow), Ho (red), Er (pink), and Yb (clear).

Single crystal growth using Bridgman method etc

Group in charge
Optical Single Crystals Group

NAKAMURA, Masaru

A single crystal grown via the Bridgman method. The 4 cm bullet-shaped metallic crystal has a mirror-like silvery luster, indicating a highly ordered internal structure and high purity.

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 by revealing text underneath. Right: 1 µm scale SEM of an alumina layer on a spinel matrix, showing the polycrystalline 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: 1 micrometer scale, dense spherical particles. Right: 10 micrometer scale, intersecting fibers. SEMs show 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. Photos show aligned samples have higher clarity than random ones.

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: growth apparatus and entangled photon source concept. Right: 200nm AFM images and PL spectra of GaAs and InAs dots (600-1600nm).

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. Examples include a blue-white pn junction, sensors, FETs, and Ga2O3 heterodevices.

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 control. Left: 3nm model of a LaAlO3 layer on a SrTiO3 substrate. Right: 1nm atomic resolution STEM cross-section showing a neat lattice and 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

Metamaterial sensor. Top: gold and quantum well structure for photocurrent. Bottom: E-field resonance, 1 micrometer SEM image, and a 5 mm packaged practical device.

Formation of waveguide type nonlinear optical element by lithography

Group in charge
Quantum Photonics Group

KURIMURA, Sunao

Phase matching and photon pairs. Top: periodic waveguide. Table: Type 0 has a d33 of 25 pm/V and efficiency of 1. Types I/II have d-constants of 5 and 1/25 efficiency.

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 under a magnetic field. This shows orientation control for ceramics.
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