Center for Crystal Researches 中山大學晶體研究中心

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NEWS

A 50 million technology transfer project of the 6-inch crystal growth awarded to NSYSU
Lithuania and Taiwan cooperation: helping develop the promising thin disk laser
Taiwan and Lithuania Center for Semiconductors and Materials Science established in Lithuania with focus on Taiwan’s laser Technology
A New Era of Cooperative Tie between Taiwan and the Baltic States - the Opening Ceremony of Taiwan and the Baltic States Research Center on Physics

ABOUT

Taiwan Consortium of Emergent Crystalline Materials (TCECM) was established in National Sun Yat-sen University (NSYSU) with the funding from the Ministry of Science and Technology (MOST) of Taiwan in May 2012. As part of the consortium, Dr. Mitch Chou’s laboratory has become the key role of the TCECM, with the goal to develop novel crystalline materials and growth technologies. In addition, the TCECM is devoted to cultivate talents with core knowledge and skills for the fields of crystal growth science and technology.

With the support of the new funding from the Ministry of Education (MOE), TCECM is officially re-named as the “Center of Crystal Research” in February 2018.

Mitch Ming-Chi Chou, Ph.D.

Professor, Academy of Innovative Semiconductor and Sustainable Manufacturing, NCKU
Jointly Appointed Professor, Department of Materials and Optoelectronic Science, NSYSU
Ph.D., CREOL/School of Optics, University of Central Florida (UCF), Orlando, FL, USA

Center of Crystal Research

Crystalline material is one of the national tactical resources, and the growth of crystals is an important way to explore novel materials. Growing single crystals is a time-consuming process and there is no simple turn-key solution.

Crystalline materials are classified into two main categories:

Crystals for condensed matter physics, including high temperature superconductor, magnetic crystals, skyrmion, heavy fermion and topological insulator.
Crystals for laser, nonlinear optics, semiconductor, piezoelectric material, compound semiconductor, oxide substrate, medical image and high energy physics.

This Center has the capacity to grow crystals in both categories. Furthermore, we also have the knowledge and experience to design crystal growth furnaces for different applications.

The research team is led by Chair Professor Mitch M.C. Chou from the Department of Materials and Optoelectronic Science at NSYSU. Dr. Chou has extensive experience in the field of crystal growth science and he received the “Award for Outstanding Contributions in Science and Technology” from the Executive Yuan of Taiwan in 2014.

CRYSTALS

Silicon Carbide (SiC)

Silicon Carbide (SiC)

SiC belongs to the wide energy gap with high thermal conductivity and excellent electron mobility. The characteristics of SiC-based power devices exhibit high energy efficiency with low power & switching losses, high-voltage breakdown, and high-temperature high-pressure resistance. It’s widely used in the renewable energy industry such as electric vehicles, wind power and solar photovoltaic, power grid converters and inverters, etc.
Sapphire α-Al2O3

Sapphire α-Al2O3

Sapphire (α-Al2O3) crystals are widely used as the infrared optical components,
high-durability windows, and electronic wafers, which are used as the insulating substrates of special-purpose solid-state electronics (especially integrated circuits and GaN-based LEDs).
Doubly-doped scintillator Ca+Ce:(Lu1-yYy)2-xSiO5

Doubly-doped scintillator
Ca+Ce:(Lu1-yYy)2-xSiO5

Doubly-doped scintillator Ca+Ce:(Lu1-yYy)2-xSiO5 can be cut into pixels and arranged in an array configuration so as to provide position sensitivity. Such arrays are often used in Positron Emission Tomography (PET) to detect cancer cell and Alzheimer’s disease; also used as a detector in High Energy Physics (HEP).
Crystals for Quantum Memory

Crystals for Quantum Memory

Quantum memory (QM) is the key element of a rapidly developing new branch of science - quantum informatics. The most prospective schemes of QM realized so far are based on rare earth (RE) ions doped oxide and fluoride single crystals (Tm: Y3Al5O12, Er:Y2SiO5 (YSO), RE3+: YPO4 & Er: LiYF4).
Ce:Y3Al5O12 (YAG) and Yb:YAG

Ce:Y3Al5O12 (YAG) and Yb:YAG

Ce>4%:Y3Al5O12 (YAG) is commonly used as a phosphor in cathode ray tubes, white light-emitting diodes, and as a scintillator. Yb>5%: YAG is an active laser medium lasing at 1030 nm, with a wide absorption band at 940 nm. It is one of the most useful medium for high-power diode-pumped solid state lasers.
Laser crystals and nonlinear crystals

Laser crystals and nonlinear crystals

Laser crystals mainly for infrared emission and scintillator crystals, including Ho:LiYF4Er:LIYF4, Cr:YVO4, Nd:YVO4, Cr:LiSrAlF6 (LiSAF), Cr+Mg: Gd3Sc2Ga3O12 (GSGG), Tm+Ce:YAlO3.
Topological insulator and topological superconductor

Topological insulator and topological superconductor

A topological insulator is a material with non-trivial symmetry protected by topological order that behaves as an insulator in its interior but its surface contains conducting states, meaning that electrons can only move along the surface of the material. By doping transition metal, it might become a superconductor. Examples of as-grown crystals include Cu:Bi2Se3 , Cu:Sb2Te(3-x)Sex, Cu:BixSb(2-x)Te3.

RESEARCH TOPICS

Exploration of new high temperature superconductor (HTSC)

Explore superconductors containing rare earth (RE) elements. The guiding idea is from both BCS theory and Jahn-Teller (JT) effect.

High power laser crystal and nonlinear optical crystal

Develop highly doped laser crystal Yb: Y3Al5O12(YAG) and Nd: Gd3Ga5O12(GGG) and other nonlinear crystals. We have the capacity to process these crystals and build a laser cavity.

Soft crystalline material

Synthesize and design soft material with long range order crystal structure, including the preparation of mesoporous materials templated by block copolymers and metal-organic framework, which could be used in gas storage, chemical sensing and energy storage.

Thermoelectric crystal and theoretical phase diagram

A thermoelectric material creates voltage when there is temperature difference on each side. This effect can be used to generate electricity and measure the temperature of objects.

FACILITIES

The Center of Crystal Research has 12 growth furnaces in the lab for bulk crystals grown by multi-functional Czochralski pulling method (Cz), resistance heating floating zone (RHFZ), Bridgeman method, and flux growth method. In addition, a hydride vapor phase epitaxy (HVPE) furnace for the epitaxial growth of III-V compound semiconductor, a Molecular beam epitaxy (MBE) for the growth of Zn1-xMgxO multiple quantum well (MQW) devices and several chemical vapor deposition (CVD) furnaces for the growth of nanomaterials. The Center also has the capacity of analyzing the microstructure and defects of crystalline materials, including TEM, Raman spectra, AFM, and high resolution XRD.

Czochralski (Cz) furnace

Czochralski (Cz) furnace

Czochralski (Cz) process is a method of crystal growth employed to obtain single crystals. It is named after Polish scientist Jan Czochralski who invented the method in 1915. Single crystal substrates such as LiAlO2, LiGaO2, NdGaO3 are used for the epitaxial growth of nonpolar III-V (GaN、InN & AlN) and II-VI (ZnO) compound semiconductors.
Multifunctional Czochralski furnace

Multifunctional Czochralski furnace

Multifunctional Czochralski furnace is used for the growth of oxide substrates with spinel and pervoskite structures such as LaAlO3, MgAl2O4, Sr2AlTaO6, LSAT、DyScO3、GdScO3 and piezoelectric crystal such as La3Ga5SiO14 & Ca3NbGa3Si2O14…etc.
Hydride Vapour Phase Epitaxy (HVPE)

Hydride Vapour Phase Epitaxy (HVPE)

Hydride Vapour Phase Epitaxy (HVPE) is an epitaxial growth technique employed to grow GaN, InN and Ga2O3, in which hydrogen chloride is reacted with metals to produce gaseous metal chlorides, which then react with ammonia to produce nitrides. Carrier gasses commonly used include ammonia, hydrogen and various chlorides.
Resistance-heated floating zone (RHFZ)

Resistance-heated floating zone (RHFZ)

Resistance-heated floating zone (RHFZ) is a method of purifying crystals, in which a narrow region of a crystal is melted, and this molten zone is moved along the crystal. The as-grown crystals include topological insulator: p-type Bi2Se3, Bi2Te3, Cu:Bi2Se3, Sb2Te(3-x)Sex and BixSb2-xTe3, Cu2O crystal - large Rydberg excitons and paramagnetic crystal Tb3Ga5O12.
Bridgman–Stockbarger furnace

Bridgman–Stockbarger furnace

Bridgman–Stockbarger technique is named after the Harvard physicist P.W. Bridgman and the MIT physicist D.C. Stockbarger. It is adopted to grow high temperature superconductor (HTSC), heavy fermion LiV2O4, superconductor LiTi2O4 and antiferromagnetic crystal MnF2.
Seebeck coefficient and electrical resistivity measuring system

Seebeck coefficient and electrical resistivity measuring system

Seebeck coefficient and electrical resistivity measuring system (ULVAC ZEM-3) measures thermoelectric materials and the temperatures measured range from -130°C to 1,000°C.
Molecular Beam Epitaxy (MBE)

Molecular Beam Epitaxy (MBE)

Molecular Beam Epitaxy (MBE) is for the epitaxial growth of wurtzite ZnO and cubic ZnO materials. CreaTec SY094 with oxygen plasma system (300W), three effusion cells (Zn, Mg and others), RHEED, and RGA.
Raman Spectroscopy

Raman Spectroscopy

Raman spectroscopy is typically used to determine the vibrational, rotational and other low-frequency modes of materials. It relies upon inelastic scattering of photons, known as Raman scattering. A source of monochromatic light, from a laser in the visible, near infrared, or UV range is used.
SiC Furnace

SiC Furnace

Physical Vapor Transport (PVT) is a method for growing bulk SiC single crystals. The grown material is controlled by a particular temperature gradient. Sublimation growth of SiC raw material occurs at high temperature zone, then transports through the growth chamber and deposits on the relatively cold crystal seed.