Temperature dependence of the critical points of monolayer MoS2 by ellipsometry
- Authors
- Park, Han Gyeol; Kim, Tae Jung; Kim, Hwa Seob; Yoo, Chang Hyun; Barange, Nilesh S.; Le, Van Long; Kim, Hyoung Uk; Senthilkumar, Velusamy; Le, Chinh Tam; Kim, Yong Soo; Seong, Maeng-Je; Kim, Young Dong
- Issue Date
- 2016
- Publisher
- TAYLOR & FRANCIS INC
- Keywords
- Molybdenum disulfide (MoS2); ellipsometry; dielectric function; temperature dependence; critical point
- Citation
- APPLIED SPECTROSCOPY REVIEWS, v.51, no.7-9, pp 621 - 635
- Pages
- 15
- Journal Title
- APPLIED SPECTROSCOPY REVIEWS
- Volume
- 51
- Number
- 7-9
- Start Page
- 621
- End Page
- 635
- URI
- https://scholarworks.bwise.kr/cau/handle/2019.sw.cau/8689
- DOI
- 10.1080/05704928.2016.1166436
- ISSN
- 0570-4928
1520-569X
- Abstract
- We report the complex pseudodielectric function < epsilon > = < epsilon(1) > + i < epsilon(2) > of molybdenum disulfide (MoS2) monolayers for energies from 1.40 to 6.42 eV and temperatures from 35 to 350 K. MoS2 was grown as a continuous monolayer on a SiO2/Si substrate in a two zone hot-wall furnace using a catalyst-free chemical vapor growth process. The monolayer was then transferred onto a sapphire substrate. We investigated the optical properties of MoS2 using a dual-rotating-compensator ellipsometer with the sample in ultrahigh vacuum to prevent degradation and to minimize condensation artifacts in the data at low sample temperatures. Critical-point (CP) energies were determined using numerically calculated second energy derivatives of the spectra. At low temperature, we observed a splitting of A-excitonic peak. This identifies the bound excitonic states, including negatively charged excitons, trion states in monolayer MoS2. Splitting of the B-excitonic peak is also indicated. Blue shifts of the CP energies and enhanced structures with reduced electron-phonon interaction are observed as the temperature is lowered. The temperature dependences of the CP energies were fit to a phenomenological expression that contains the Bose-Einstein statistical factor and the temperature coefficient.
- Files in This Item
- There are no files associated with this item.
- Appears in
Collections - College of Natural Sciences > Department of Physics > 1. Journal Articles
![qrcode](https://api.qrserver.com/v1/create-qr-code/?size=55x55&data=https://scholarworks.bwise.kr/cau/handle/2019.sw.cau/8689)
Items in ScholarWorks are protected by copyright, with all rights reserved, unless otherwise indicated.