Terahertz Quantum Device Research Team

We develop advanced terahertz emitting and sensing devices based on inter sub-band optical transition of semiconductor quantum cascade structures. Firstly, we design and fabricate novel quantum cascade superlattice (SL) structures for high-efficiency terahertz transitions and develop terahertz quantum cascade laser (QCLs) with frequency range between 1-100 THz. We also develop high-sensitivity terahertz-wave detectors and terahertz-infrared (IR) light modulators using inter sub-band absorption of quantum wells. We hope through this research to construct what will become the base of the next-generation advanced terahertz imaging system.

Research Fields

Physics / Engineering / Materials Sciences

Research Subjects

• Research toward the realization of higher temperature operation of QCL
• Research toward the realization of 5-12 THz-band QCL using nitride semiconductors

Publications

1. Lin, T.T., Ying, L., and Hirayama, H.
   Threshold current density reduction by utilizing high-Al-composition barriers in 3.7 THz GaAs/AlGaAs quantum cascade lasers
   Appl. Phys. Express, Vol. 5, 012101 (2011).
2. Terashima, W. and Hirayama, H.
   Development of terahertz quantum cascade laser based on III-nitride semiconductors
   The Review of Laser Engineering, Vol. 39, No. 10, pp. 769-774 (2011).
3. Terashima, W. and Hirayama, H.
   Molecular beam epitaxy growth of GaN/AlGaN quantum cascade structure using droplets elimination by thermal annealing technique
   Phys. Status Solidi A 208, No. 5, pp. 1187-1190 (2011).
4. Terashima, W. and Hirayama, H.
   Spontaneous emission from GaN/AlGaN terahertz quantum cascade laser grown on GaN substrate
   Phys. Status Solidi C, Vol. 8, pp. 2302-2304 (2011).
5. Mino, T., Hirayama, H., Takano, T., Tsubaki, K. and Sugiyama, M.
   Characteristics of epitaxial lateral overgrowth AlN template on (111)Si substrates for AlGaN deep-UV LEDs fabricated on different direction stripe patterns
   Phys. Status Solidi C, Vol. 9, pp. 802-805 (2012).
6. Fujikawa, S., Hirayama, H. and Maeda, N.
   High-Efficiency AlGaN Deep-UV LEDs fabricated on a- and m-axis oriented c-plane sapphire substrates
   Phys. Status Solidi C, Vol. 9, pp. 790-793 (2012).
7. Mino, T., Hirayama, H., Takano, T., Tsubaki, K. and Sugiyama, M.
   Realization of 256-278 nm AlGaN-based Deep-Ultraviolet Light-Emitting Diodes on Si Substrates Using Epitaxial Lateral Overgrowth AlN Templates
   Applied Physics Express 4, 092104 (2011).
8. Fujikawa, S. and Hirayama, H.
   284-300 nm quaternary InAlGaN-based deep-ultraviolet light-emitting diodes on Si(111) substrates
   Applied Physics Express 4, 061002 (2011).
9. Terashima, W. and Hirayama, H.
   The Utility of Droplet Elimination by Thermal Annealing Technique for Fabrication of GaN/AlGaN Terahertz Quantum Cascade Structure by Radio Frequency Molecular Beam Epitaxy
   Appl. Phys. Express, Vol. 3, No. 12, 125501-1-3 (2010).
10. Ying, L., Horiuchi, N. and Hirayama, H.
    Ag-metal bonding condition for low-loss double-metal waveguide of terahertz quantum cascade laser
    Jap. J. Appl. Phys., Vol. 47, No. 10, 7926-7928 (2008).