Novel terahertz NEMS bolometers by using two-dimensional nanomaterials

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K15023
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 21050:Electric and electronic materials-related
• Research Institution: Tokyo University of Agriculture and Technology
• Principal Investigator: Zhang Ya 東京農工大学, 工学(系)研究科(研究院), 准教授 (80779637)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: テラヘルツ / グラフェン / 2次元材料 / 光センサ

Outline of Final Research Achievements

Two-dimensional materials such as graphene have a very small heat capacity and in-plane thermal conductance, and thus are very promising for realizing sensitive and fast terahertz thermal sensors. By using CVD-grown graphene, we have developed a photodetector with a suspended graphene layer and two different types of metal electrodes. When irradiated with the input light, the graphene film is heated up, and the Seebeck effect causes a voltage output between the two electrodes (Au-Al). We have found that when the input light power< 2mW, the photodetector gives a responsivity of ~90 V/W. Moreover, when the modulation frequency of the incident light is increased from 100 Hz to 1 kHz, there is no observable decrease in the optical response, indicating that the thermal time constant is very small. The result shows that the fabricated graphene photodetector will be useful for realizing sensitive and fast terahertz sensors.

Free Research Field

半導体デバイス　テラヘルツ技術

Academic Significance and Societal Importance of the Research Achievements

テラヘルツ・赤外領域の分光・検出技術は、基礎科学、医学・薬学、製造業、安全・安心分野など様々な分野への応用として注目されている。このような技術を社会の様々な場面で広く応用展開していくためには、極低温への冷却を必要としない高感度・高速のテラヘルツ・赤外検出用ボロメータの開発が必要不可欠である。本研究では、新規な2次元ナノ材料を用いたボロメータの動作原理を検証し、2次元ナノ材料の超低熱容量・超低熱伝導のメリトを利用して超高速・高感度ボロメータの実現を可能にする。そのため、本研究はテラヘルツ・赤外光を利用する産業分野に寄与する。