2019 Fiscal Year Research-status Report
Development of low-frequency terahertz quantum cascade lasers for high-speed wireless communications applications
| Project/Area Number |
19K15052
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| Research Institution | Institute of Physical and Chemical Research |
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Principal Investigator |
王 利 国立研究開発法人理化学研究所, 光量子工学研究センター, 特別研究員 (50804035)
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| Project Period (FY) |
2019-04-01 – 2021-03-31
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| Keywords | THz-QCL / 1.8THz |
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| Outline of Annual Research Achievements |
1. more efficient and more reliable simulation package based on non-equilibrium Green's function has been achieved: first, the whole simulation package is set working at parallel computing mode, making to obtain the optical gain in less than 2 hours; second, scattering rate between the basic laser quantum states is resulted, it is very useful to understand the lasing process in new design structures; third, assisted-scattering scheme based on four-wells is predicted in which the optical gain can reach up 40/cm at 230K. 2. high crystal growth of superlattice GaAs/Al0.2Ga0.8As with each layer thickness less than 1% fluctuation is realized, in addition, more reliable processing of Au-Au metals waveguides is done. lasing of 1.8THz at 170K is achieved at present.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
1. the target for improving the simulation package is realized: the computing mode is transferred to parallel and also the electron-electron interactions for scattering effect on the optical gain is modeled, resulting in the calculation more reliable;
2. the initial lasing devices are realized, based on those results, the further optimization direction is clarified.
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| Strategy for Future Research Activity |
the main plan is to optimized the experiments processing as, at present, the design of QCL structures is already completed. In detail, first, Al0.25Ga0.75As barrier will be introduced to suppress the parasitic leakage channels, sharp interface within 1 monolayer should be achieved, meanwhile, the 2D doping levels will be increased from 3.5E10/cm2 to 5E10/cm2; second, Cu-Cu metal waveguide will developed instead of Au-Au, for better high-temperature operations. the optimized annealing temperature will be developed to avoid micro-cracks in Cu-Cu metals.
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| Causes of Carryover |
Due to the Cov-19 virus spread, the article costs for purchasing the high-purity k-cell Al metals is delayed to the next fiscal year, the total amount will be increased. in addition, mask patterns for Cu-Cu metals will be designed separately.
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