A Caltech Library Service

Refractive Index Modulation in Monolayer Molybdenum Diselenide

Li, Melissa and Biswas, Souvik and Hail, Claudio U. and Atwater, Harry A. (2021) Refractive Index Modulation in Monolayer Molybdenum Diselenide. Nano Letters, 21 (18). pp. 7602-7608. ISSN 1530-6984. doi:10.1021/acs.nanolett.1c02199.

[img] PDF (Additional experimental and simulation details, materials, and methods, including Figures S1–S13 with fringe images and interferometry data) - Supplemental Material
See Usage Policy.


Use this Persistent URL to link to this item:


Two-dimensional transition metal dichalcogenides are promising candidates for ultrathin light modulators due to their highly tunable excitonic resonances at visible and near-infrared wavelengths. At cryogenic temperatures, large excitonic reflectivity in monolayer molybdenum diselenide (MoSe₂) has been shown, but the permittivity and index modulation have not been studied. Here, we demonstrate large gate-tunability of complex refractive index in monolayer MoSe2 by Fermi level modulation and study the doping dependence of the A and B excitonic resonances for temperatures between 4 and 150 K. By tuning the charge density, we observe both temperature- and carrier-dependent epsilon-near-zero response in the permittivity and transition from metallic to dielectric near the A exciton energy. We attribute the dynamic control of the refractive index to the interplay between radiative and non-radiative decay channels that are tuned upon gating. Our results suggest the potential of monolayer MoSe₂ as an active material for emerging photonics applications.

Item Type:Article
Related URLs:
URLURL TypeDescription
Li, Melissa0000-0003-1534-4191
Hail, Claudio U.0000-0001-6553-5135
Atwater, Harry A.0000-0001-9435-0201
Additional Information:© 2021 American Chemical Society. Received 4 June 2021. Revised 28 August 2021. Published online 1 September 2021. The authors thank Cora Went, Joeson Wong, and Hamidreza Akbari for fruitful discussions and feedback on the work. The authors gratefully acknowledge support from the U.S. Department of Energy, Office of Science, under grant DE-FG02-07ER46405. C.U.H. acknowledges support from the Swiss National Science Foundation through the Early Postdoc Mobility Fellowship, grant no. P2EZP2_191880. Author Contributions: M.L, S.B., and H.A.A. conceived the project. M.L. fabricated the samples with support from S.B. M.L., S.B., and C.U.H. worked on measurements. M.L. and C.U.H. performed FDTD simulations. M.L. analyzed the data and wrote the manuscript. H.A.A. supervised the project. All authors discussed the implications of the results and provided important feedback. The authors declare no competing financial interest.
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG02-07ER46405
Swiss National Science Foundation (SNSF)P2EZP2_191880
Subject Keywords:2D materials; transition metal dichalcogenides; monolayer semiconductor; optical modulator; tunable optical properties; photonics
Issue or Number:18
Record Number:CaltechAUTHORS:20210917-215613673
Persistent URL:
Official Citation:Refractive Index Modulation in Monolayer Molybdenum Diselenide. Melissa Li, Souvik Biswas, Claudio U. Hail, and Harry A. Atwater. Nano Letters 2021 21 (18), 7602-7608; DOI: 10.1021/acs.nanolett.1c02199
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:110949
Deposited By: George Porter
Deposited On:20 Sep 2021 14:49
Last Modified:23 Sep 2021 18:08

Repository Staff Only: item control page