Interband Transitions in Monolayer and Few-Layer WSe2 Probed Using Photoexcited Charge Collection Spectroscopy

Kyunghee Choi; Kimoon Lee; Sanghyuck Yu; Sehoon Oh; Hyoung Joon Choi; Heesun Bae; Seongil Im

doi:10.1021/acsami.8b04056

Interband Transitions in Monolayer and Few-Layer WSe₂ Probed Using Photoexcited Charge Collection Spectroscopy

ACS Appl Mater Interfaces. 2018 Jun 20;10(24):20213-20218. doi: 10.1021/acsami.8b04056. Epub 2018 Jun 11.

Authors

Kyunghee Choi¹, Kimoon Lee², Sanghyuck Yu³, Sehoon Oh³, Hyoung Joon Choi³, Heesun Bae³, Seongil Im³

Affiliations

¹ Reality Display Device Research Group , Electronics and Telecommunications Research Institute , 218 Gajeong-ro, Yuseong-gu , Daejeon 34129 , Republic of Korea.
² Department of Physics , Kunsan National University , Gunsan 54150 , Republic of Korea.
³ Department of Physics , Yonsei University , 50 Yonsei-ro, Seodaemun-gu , Seoul 03722 , Republic of Korea.

PMID: 29882405
DOI: 10.1021/acsami.8b04056

Abstract

Transition-metal dichalcogenides are currently under rigorous investigation because of their distinct layer-dependent physical properties originating from the corresponding evolution of the band structure. Here, we report the highly resolved probing of layer-dependent band structure evolution for WSe₂ using photoexcited charge collection spectroscopy (PECCS). Monolayer, few-layer, and multilayer WSe₂ can be probed in top-gate field-effect transistor platforms, and their interband transitions are efficiently observed. Our theoretical calculations show a great coincidence with the PECCS results, proving that the indirect Γ-K and Γ-Λ transitions as well as the direct K-K transition are clearly resolved in multilayer WSe₂ by PECCS.

Keywords: WSe2; field-effect transistor; first-principles calculation; interband transition; transition-metal dichalcogenide.