Professor T. S. Iwayama (PhD)

Address of Institution:

Department of Physics
Aichi University of Education
Igaya-cho, Kariya-shi
Aichi 448-8542, JAPAN

Phone & Fax:

+81-566-26-2637

E-mail:

tiwayama(at)auecc.aichi-edu.ac.jp

Dr.T.S.Iwayama was born in Tokyo, Japan. He obtained BSc in Physics at Waseda University, MSc in Engineering at Nagoya Institute of Technology, and PhD degree in Physics at Nagoya University. He became a research associate at Department of Materials Science, Aichi University of Education where he was promoted to an associate professor. 1996-1997, he joined School of Chemistry, Physics and Environmental Science (CPES), University of Sussex, U.K., as a visiting research fellow. 1998-1999, he was a visiting academic at Department of Electronic and Electrical Engineering, University College London, U.K.. He is now a professor at Department of Physics, Aichi University of Education.

Field of Specialization:

Semiconductor Physics, Materials Engineering, Silicon Photonics

Key Words:

Semiconductor Nanocrystals, Optical Effects, Ion Implantation, Pulsed Laser Deposition, Laser Ablation, Optoelectronic Devices

Current Research:

My group is concerned with the control and applications of semiconductor nanocrystal, and ion and light (Ultra-violet, Infra-red and Visible) irradiation effects on materials.

The goal of fabricating electroluminescent devices on silicon is a major challenge world wide but the current methods of forming porous silicon are proving ineffective, particularly in relation to the effort expended. However the ion implanted semiconductor nanocrystals have shown remarkable advances from my group.

Ion implantation in insulators to modify surface properties of insulating materials is scientifically challenging and has an enormous number of potential applications. We have focused on the formation of semiconductor nanocrystals in insulating materials, and developed the first examples of luminescent silicon nanocrystals inside of silica glass and thermal oxide film on silicon wafer using ion implantation.

Pulsed laser surface treatments can control radiation induced damage and crystallinity of semiconductor nanocrystals formed by implantation. The same high power Ultra-violet and Visible pulsed lasers are also used for ablation thin film deposition.

Ion and/or laser beam synthesis of semiconductor nanocrystals is a potential candidate for the method of manufacturing nanoclusters of a pure and well-regulated condition as not only for basic research but also for application for optoelectronic devices. We are trying to make strong progress in the empirical production of more efficient devices using semiconductor nanocrystals, using ion beams.

Formation Process of Implanted Si Nanocrystals

HR-TEM Image & Photoluminescence of Si Nanocrystals

Model for Photoluminescence

RTA Effects

FA: Furnace Anneals, RTA: Rapid Thermal Anneals

Some Selected Publications:

• Visible photoluminescence in Si⁺-implanted silica glass, J. Appl. Phys. 75, 7779 (1994).
• Visible photoluminescence in Si⁺-implanted thermal oxide films on crystalline Si, Appl. Phys. Lett. 65, 1814 (1994). [Full text] (PDF)
• Optical properties of silicon nanoclusters fabricated by ion implantation, J. Appl. Phys. 83, 6018 (1998). [Full text] (PDF)
• Mechanism of photoluminescence of Si nanocrystals in SiO₂ fabricated by ion implantation: the role of interactions of nanocrystals and oxygen, J. Phys.: Condens. Matter 11, 6595 (1999). [Full text] (PDF)
• Evidence of energy coupling between Si nanocrystals and Er³⁺ in ion-implanted silica thin films, Appl. Phys. Lett. 75, 2011 (1999). [Full text] (PDF)
• Characterisation of silicon nanocrystals in silica and correlation with luminescence, Inst. Phys. Conf. Ser. 161, 589 (1999). [Full text] (PDF)
• Characterization of Si nanocrystals grown by annealing SiO₂ films with uniform concentrations of implanted Si, J. Appl. Phys. 88, 3954 (2000). [Full text] (PDF)
• Broad-band and flashlamp pumping of 1.53um emission from erbium-doped silicon nanocrystals, Mater. Sci. Eng. B 81, 19 (2001). [Full text] (PDF)
• Characteristic photoluminescence properties of Si nanocrystals in SiO₂ fabricated by ion implantation and annealing, Solid-State Electronics 45, 1487 (2001). [Full text] (PDF)
• Luminescence from erbium-doped silicon nanocrystals in silica: excitation mechanisms, J. Appl. Phys. 91, 367 (2002).
• Laser photolysis studies of the reaction of chromium(III) octaethylporphyrin complex with triphenylphosphine and triphenylphosphine Oxide, Inorg. Chem. 44, 6445 (2005).
• Enhanced luminescence from encapsulated silicon nanocrystals in SiO₂ with rapid thermal anneal, Vacuum 81, 179 (2006).
• Lamp annealing effects on the formation process of implanted silicon nanocrystals in SiO₂, Nucl. Instrum. Methods B 257, 85 (2007).

Collaboration with:

• Kanazawa University (Japan)
• Shibaura Institute of Technology (Japan)
• Waseda University (Japan)
• High Energy Accelerator Research Organization, KEK (Japan)
• National Institute of Advanced Industrial Science and Technology Chubu, AIST (Japan)
• University of Sussex (U.K.)
• University College London (U.K.)
• University of Cambridge (U.K.)
• Naval Research Laboratory (U.S.A.)
• Lawrence Livermore National Laboratory (U.S.A.)