Development of time resolved STM-THz-TDS system for studying the ultrafast carrier dynamics of graphene

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K14153
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 30020:Optical engineering and photon science-related
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Jaculbia Rafael 国立研究開発法人理化学研究所, 開拓研究本部, 訪問研究員 (40777299)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: Terahertz / SPM / Nanomaterials / Nanospectroscopy / tip enhancement

Outline of Final Research Achievements

In this project, three types of nanospectroscopy system was developed which utilizes Terahertz (THz) radiation and scanning probe microscopy (SPM). Owing to this combination, our setup allows for the investigation of various materials with nanoscale dimensions. In one compact arrangement, our system is composed of SPM THz time domain spectroscopy (SPM-THz-TDS), SPM optical pump-probe spectroscopy (SPM-OPTP), and SPM laser terahertz emission microscopy (SPM-LTEM). Switching between all of these setups is achieved by movement of flip mirrors and fixing other parts such as the delay stage. Moreover, we placed all of the critical components such as the THz related optics, the SPM, and other electronics inside a vacuum sealable box. This configuration was done in order to reduce the noice as well as to avoid water vapor absorption of the THz radiation. Using these setups, we have investigated low temperature grown GaAs, InAs and CVD grown graphene samples.

Free Research Field

Optics

Academic Significance and Societal Importance of the Research Achievements

To find the practical applications of newly discovered nanomaterials, understanding their properties is crucial. Our developed setup allows us to investigate these new nanomaterials. Full understanding of these sample properties would then lead to the discovery of their practical applications.