Chief Scientist Laboratories Quantum Optodevice Laboratory
Chief Scientist: Hideki Hirayama (D.Eng.)
The development of new-frequency semiconductor light sources, such as deep-ultraviolet (DUV) light-emitting diodes (LEDs) and laser diodes (LDs) or terahertz quantum-cascade lasers (THz-QCLs) is one of the most important subjects, because they are strongly required for a wide variety of potential applications, e.g. sterilization, water and air purification, medicine and biochemistry, light sources for high density optical recording, white light illumination and non-destructive see-through examinations. The Quantum Optodevice Laboratory's research is at the forefront of optics and nanotechnology, e.g. in creating innovative optical devices, including undeveloped frequency semiconductor emitters, and in developing a new research field through merging advanced optical/laser science, atomic/nano-scale material fabrication technology, novel semiconductor crystal growth technologies, and so forth. Through the introduction of novel crystal growth technology for wide-gap semiconductors, we have achieved innovative emitting devices such as highly efficient DUV-LEDs with the shortest wavelength regime (220-350nm), or THz-QCLs. We have also investigated the performance limits of these devices by introducing innovative quantum heterostructures and/or photonic nano-structures. Through the creation of the applicable field of these new emitting devices, we aim to contribute to the realization of a richer human society.
Main Research Fields
Related Research Fields
- Interdisciplinary Science & Engineering
- Electron device, Electronic equipment
- Optical engineering, Photon science
- Nitride Semiconductors
- Quantum cascade laser
- Crystal growth
- Inter-subband transition
- 1.Takano, T., Mino, T., Sakai, J., Noguchi, and Hirayama, H.:
"Deep-ultraviolet light-emitting diodes with external quantum efficiency higher than 20% at 275 nm achieved by improving light-extraction efficiency"
Applied Physics Express, Vol. 10, No. 3, pp. 031002-1-4 (2017).
- 2.Yun, J. and Hirayama, H.:
"Investigation of the light-extraction efficiency in 280 nm AlGaN-based light-emitting diodes having a highly transparent p-AlGaN contact layer"
Journal of Applied Physics, Vol. 121, No. 1, 013105-1-9 (2017).
- 3.Jo, M., Oshima, I., Matsumoto, T., Maeda, N., Kamata, N. and Hirayama, H:
"Structural and electrical properties of semipolar (11‐22) AlGaN grown on m‐plane (1‐100) sapphire substrates"
physica status solidi c, Vol. 14, No. 8, pp. 1600248-1-3 (2017).
- 4.Tran, B. T., Hirayama, H., Jo, M., Maeda, N., Inoue, D. and Kikitsu, T.:
"High-quality AlN template grown on a patterned Si (111) substrate"
Journal of Crystal Growth, Vol. 468, No. 15, pp. 225-229 (2017).
- 5.Tran, B. T., Maeda, N., Jo, M., Inoue, D., Kikitsu, T. and Hirayama, H:
"Performance improvement of AlN crystal quality grown on patterned Si (111) substrate for deep UV-LED applications"
Scientific Reports, Vol. 6, Article number. 35681 (2016).
- 6.Jo, M., Maeda, N. and Hirayama, H:
"Enhancement of light extraction efficiency in 260 nm light-emitting diode with a highly transparent p-AlGaN layer"
App. Phys. Express, Vol. 9, No. 1, p. 01202-1-3 (2016).
- 7.Tran, B. T., Hirayama, H., Maeda, N., Jo, M., Toyoda, S. and Kamata, N.:
"Direct growth and controlled coalescence of thick AlN template on micro-circle patterned Si substrate"
Scientific Report, Vol. 5, pp. 14734 (2015).
- 8.Yun, J., Shim, J. I. and Hirayama, H.:
"Analysis of efficiency droop in 280 nm AlGaN multiple-quantum-well light-emitting diodes based on carrier rate equation"
Appl. Phys. Express, Vol. 8, No. 2, pp. 022104-1-3 (2015).
- 9.Hirayama, H., Maeda, N., Fujikawa, S., Toyoda, S. and Kamata, N.:
"Recent progress and future prospects of AlGaN-based high-efficiency deep-ultraviolet light-emitting diodes"
Jap. J. Appl. Phys. (Selected Topic), Vol. 53, No. 10, pp. 100209 1-10 (2014).
- 10.Lin, T. T. and Hirayama, H.:
"Improvement of operation temerature in GaAs/AlGaAs THz-QCLs by utilizing high Al conposition barrier"
Phys. Status Solidi (c), Vol. 10, No. 11, pp. 1430-1433 (2013).
Recent Research Results
Annual research report
- Hideki Hirayama
- Chief Scientist
- Noritoshi Maeda
- Research Scientist
- Yukio Kashima
- Technical Staff II
- Eriko Matsuura
- Visiting Technician
Cooperation Center, W514
2-1 Hirosawa, Wako, Saitama 351-0198, Japan
Email: hirayama [at] riken.jp