Photoluminescence from Single-Walled MoS2 Nanotubes Coaxially Grown on Boron Nitride Nanotubes

Ming Liu; Kaoru Hisama; Yongjia Zheng; Mina Maruyama; Seungju Seo; Anton Anisimov; Taiki Inoue; Esko I Kauppinen; Susumu Okada; Shohei Chiashi; Rong Xiang; Shigeo Maruyama

doi:10.1021/acsnano.0c10586

Photoluminescence from Single-Walled MoS₂ Nanotubes Coaxially Grown on Boron Nitride Nanotubes

ACS Nano. 2021 May 25;15(5):8418-8426. doi: 10.1021/acsnano.0c10586. Epub 2021 Apr 21.

Authors

Affiliations

¹ Department of Mechanical Engineering, The University of Tokyo, Tokyo 113-8656, Japan.
² Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8571, Japan.
³ Canatu Ltd., Helsinki FI-00390, Finland.
⁴ Department of Applied Physics, Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan.
⁵ Department of Applied Physics, Aalto University School of Science, Espoo 15100, Aalto FI-00076, Finland.

PMID: 33881302
DOI: 10.1021/acsnano.0c10586

Abstract

Single-walled and multiwalled molybdenum disulfide (MoS₂) nanotubes have been coaxially synthesized on small-diameter boron nitride nanotubes (BNNTs) that are obtained from removing single-walled carbon nanotubes (SWCNTs) in heteronanotubes of SWCNTs coated by BNNTs. The photoluminescence (PL) from single-walled MoS₂ nanotubes supported by core BNNTs is observed in this work, which evidences the direct bandgap structure of single-walled MoS₂ nanotubes with a diameter around 6-7 nm. The observation is consistent with our DFT results that the single-walled MoS₂ nanotube changes from an indirect-gap to a direct-gap semiconductor when the diameter of a nanotube is more than around 5.2 nm. On the other hand, when there are SWCNTs inside the heteronanotubes of BNNTs and single-walled MoS₂ nanotubes, the PL signal from MoS₂ nanotubes is considerably quenched. The charge transfer and energy transfer between SWCNTs and single-walled MoS₂ nanotubes were examined through characterizations by PL, X-ray photoelectron spectroscopy, and Raman spectroscopy. Moreover, the PL signal from multiwalled MoS₂ nanotubes is significantly quenched. Single-walled and multiwalled MoS₂ nanotubes exhibit different Raman features in both resonant and nonresonant Raman spectra.

Keywords: Raman spectroscopy; bandgap; molybdenum disulfide nanotubes; one-dimensional heterostructure; photoluminescence; single-walled carbon nanotubes.