ED2012-103 高Al組成AlGaAsを用いたTHz-QCLsの高温動作特性改善(ミリ波・テラヘルツ波デバイス・システム)

概要

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Terahertz quantum cascade lasers (THz QCLs) are unipolar intersubband transition semiconductor THz source with narrow linewidth and high output power. They have been earnest to operate near room temperature in order to realize compact size THz applications without cooling system. Current limited maximum operation temperature (Tmax) 199.5 K is reported by a state-of-the-art longitudinal optical (LO) phonon depopulation scheme GaAs/Al0.15Ga0.85As structure. Here we propose the operation temperature performance improvement by utilizing high Al composition AlGaAs in THz QCLs and succsefully increase the Tmax of a 4-well resonant tunneling (RT) LO phonon scheme THz QCLs about 10 K. The deep well potential and increase total LO phonon energy will increase the design freedom and improve the thermal performances. It have the advantage of (1) Reduce Jth at high temperature operation region and increase device characteristic temperature (T0). Because higher LO phonon energy is expected to reduce the non-radiative leakage via LO-phonon scattering between two lasing levels. (2) Reduce thermal backfilling from ground level. Both are expected to reduce Jth at higher temperature. The high Al composition AlGaAs structure is one of the suitable designs for approaching the high temperature operation THz QCLs.
2012-12-10