Scanning near-field optical spectroscopy and carrier transport based analysis in mesoscopic regions for two-dimensional semiconductors

Anri Sakurai; Kohei Iwamoto; Yoshihiko Miwa; Hirokazu Hori; Akira Ishikawa; Kazuharu Uchiyama; Kiyoshi Kobayashi; Katsumi Kishino; Masaru Sakai

doi:10.1038/s41598-022-13492-8

Scanning near-field optical spectroscopy and carrier transport based analysis in mesoscopic regions for two-dimensional semiconductors

Sci Rep. 2022 Jun 20;12(1):10348. doi: 10.1038/s41598-022-13492-8.

Authors

Anri Sakurai¹, Kohei Iwamoto¹, Yoshihiko Miwa¹, Hirokazu Hori¹, Akira Ishikawa¹, Kazuharu Uchiyama¹, Kiyoshi Kobayashi², Katsumi Kishino³, Masaru Sakai⁴

Affiliations

¹ Department of Science and Advanced Materials, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi, 400-8511, Japan.
² Natural Science Laboratory, Toyo University, 5-28-20 Hakusan, Bunkyo-ku, Tokyo, 112-8606, Japan.
³ Sophia Nanotechnology Research Center, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo, 102-8554, Japan.
⁴ Department of Science and Advanced Materials, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi, 400-8511, Japan. sakaims@yamanashi.ac.jp.

Abstract

The measurements of photoexcited transport in mesoscopic regimes reveal the states and properties of mesoscopic systems. In this study, we focused on direct measurements of electromagnetic energy transports in the mesoscopic regions and constructed a scanning tunnelling microscope-assisted multi-probe scanning near-field optical microscope spectroscopy system. After producing an emission energy map through a single-probe measurement, two-probe measurement enables us to observe and analyse carrier transport characteristics. It suggests that exciton generation and transport in the mesoscopic region of semiconductors with quantum structure changes, such as the bias of dopant, affect the excited carrier emission recombination process. The measured probability density of the carrier transported with quantum effects can be used for applications in natural intelligence research by combining it with the analysis using tournament structures. Our developed measurement and analysis methods are expected to clarify the details of carrier's behaviour in the mesoscopic region in various materials and lead to applications for novel optoelectronic devices.