Study of plasmon effect on quantum efficiency of CSIP

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K05001
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: General applied physics
• Research Institution: National Institute of Information and Communications Technology (2017-2018); The University of Tokyo (2016)
• Principal Investigator: Kim Sunmi 国立研究開発法人情報通信研究機構, 未来ICT研究所フロンティア創造総合研究室, 研究員 (90585697)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: センサー / 量子効率 / 量子井戸 / プラズモニックアンテナ

Outline of Final Research Achievements

Charge-sensitive infrared phototransistor (CSIP) is a highly sensitive semiconductor terahertz (THz) detector with single-photon sensitivity. Due to the excitation mechanism via intersubband transition in a quantum well, the CSIP requires careful design of the photo-coupler and proper light illumination method to achieve high quantum efficiency. We have improved the quantum efficiency up to 26% by optimizing plasmonic antenna structure (such as nanogap and cross-hole array antenna) and introducing the radiation from the backside of the CSIP substrate, which leads to efficient surface plasmon excitation in the photo-coupler.
In addition to the improvement of quantum efficiency, the possibility of the selective detection with plasmonic antenna structure and the tuning of detection wavelength with gate bias was clarified.

Free Research Field

低温物理

Academic Significance and Societal Importance of the Research Achievements

ナノ Gap を含む金属ナノ構造でのプラズモン研究は高感度計測への応用が世界中で検討されている中、CSIP 素子の検出波長領域でも有る10 μm～50 μm 領域では研究が少ないため、本研究では、これを CSIP に導入することによって、この波長領域でのプラズモン特性の理解を深めると共に CSIP の量子効率向上に大きな進展をもたらした。さらに、基礎物理 のみならず、物理、バイオ、天文など広範な分野へ適用可能な計測法が提供されるため、学術的・ 産業的に非常に有意義である。