Temperature Dependence of Optical Properties of MoS<sub>2</sub> and WS<sub>2</sub> Heterostructures Assessed by Spectroscopic Ellipsometry
We report the complex dielectric function <i>ε</i> = <i>ε</i><sub>1</sub> + <i>iε</i><sub>2</sub> of MoS<sub>2</sub>/WS<sub>2</sub> and WS<sub>2</sub>/MoS<sub>2</sub> heterostructures and thei...
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2025-01-01
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| author | Hoang Tung Nguyen Van Long Le Thi Mai Nguyen Xuan Khuyen Bui Thi Giang Nguyen Nhat Linh Nguyen Xuan Au Nguyen Tae Jung Kim |
| author_facet | Hoang Tung Nguyen Van Long Le Thi Mai Nguyen Xuan Khuyen Bui Thi Giang Nguyen Nhat Linh Nguyen Xuan Au Nguyen Tae Jung Kim |
| author_sort | Hoang Tung Nguyen |
| collection | DOAJ |
| description | We report the complex dielectric function <i>ε</i> = <i>ε</i><sub>1</sub> + <i>iε</i><sub>2</sub> of MoS<sub>2</sub>/WS<sub>2</sub> and WS<sub>2</sub>/MoS<sub>2</sub> heterostructures and their constituent monolayers MoS<sub>2</sub> and WS<sub>2</sub> for an energy range from 1.5 to 6.0 eV and temperatures from 39 to 300 K. Comparisons between the optical properties of the heterostructures and their monolayers were conducted. Critical-point (CP) energies of the heterostructures were traced back to their origins in the monolayers. Low-temperature measurements confirmed the existence of only three excitonic CPs from 1.5 to 2.5 eV due to the overlap of trion <i>B</i><sup>−</sup> of the MoS<sub>2</sub> monolayer and exciton <i>A</i><sup>0</sup> of the WS<sub>2</sub> monolayer. Due to the dielectric screening effect, most CPs exhibit red shifts in the heterostructures compared to their monolayer counterparts. |
| format | Article |
| id | doaj-art-d8b964c42224420398b829d6e5b88739 |
| institution | Kabale University |
| issn | 2079-4991 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj-art-d8b964c42224420398b829d6e5b887392025-01-10T13:19:26ZengMDPI AGNanomaterials2079-49912025-01-011517610.3390/nano15010076Temperature Dependence of Optical Properties of MoS<sub>2</sub> and WS<sub>2</sub> Heterostructures Assessed by Spectroscopic EllipsometryHoang Tung Nguyen0Van Long Le1Thi Mai Nguyen2Xuan Khuyen Bui3Thi Giang Nguyen4Nhat Linh Nguyen5Xuan Au Nguyen6Tae Jung Kim7Institute of Materials Science, Vietnam Academy of Science and Technology, Hanoi 100000, VietnamInstitute of Materials Science, Vietnam Academy of Science and Technology, Hanoi 100000, VietnamInstitute of Materials Science, Vietnam Academy of Science and Technology, Hanoi 100000, VietnamInstitute of Materials Science, Vietnam Academy of Science and Technology, Hanoi 100000, VietnamInstitute of Materials Science, Vietnam Academy of Science and Technology, Hanoi 100000, VietnamInstitute of Materials Science, Vietnam Academy of Science and Technology, Hanoi 100000, VietnamDepartment of Physics, Kyung Hee University, Seoul 02447, Republic of KoreaDepartment of Physics, Kyung Hee University, Seoul 02447, Republic of KoreaWe report the complex dielectric function <i>ε</i> = <i>ε</i><sub>1</sub> + <i>iε</i><sub>2</sub> of MoS<sub>2</sub>/WS<sub>2</sub> and WS<sub>2</sub>/MoS<sub>2</sub> heterostructures and their constituent monolayers MoS<sub>2</sub> and WS<sub>2</sub> for an energy range from 1.5 to 6.0 eV and temperatures from 39 to 300 K. Comparisons between the optical properties of the heterostructures and their monolayers were conducted. Critical-point (CP) energies of the heterostructures were traced back to their origins in the monolayers. Low-temperature measurements confirmed the existence of only three excitonic CPs from 1.5 to 2.5 eV due to the overlap of trion <i>B</i><sup>−</sup> of the MoS<sub>2</sub> monolayer and exciton <i>A</i><sup>0</sup> of the WS<sub>2</sub> monolayer. Due to the dielectric screening effect, most CPs exhibit red shifts in the heterostructures compared to their monolayer counterparts.https://www.mdpi.com/2079-4991/15/1/76MoS<sub>2</sub> and WS<sub>2</sub> heterostructuresspectroscopic ellipsometrydielectric functiontemperature dependencecritical pointexciton |
| spellingShingle | Hoang Tung Nguyen Van Long Le Thi Mai Nguyen Xuan Khuyen Bui Thi Giang Nguyen Nhat Linh Nguyen Xuan Au Nguyen Tae Jung Kim Temperature Dependence of Optical Properties of MoS<sub>2</sub> and WS<sub>2</sub> Heterostructures Assessed by Spectroscopic Ellipsometry Nanomaterials MoS<sub>2</sub> and WS<sub>2</sub> heterostructures spectroscopic ellipsometry dielectric function temperature dependence critical point exciton |
| title | Temperature Dependence of Optical Properties of MoS<sub>2</sub> and WS<sub>2</sub> Heterostructures Assessed by Spectroscopic Ellipsometry |
| title_full | Temperature Dependence of Optical Properties of MoS<sub>2</sub> and WS<sub>2</sub> Heterostructures Assessed by Spectroscopic Ellipsometry |
| title_fullStr | Temperature Dependence of Optical Properties of MoS<sub>2</sub> and WS<sub>2</sub> Heterostructures Assessed by Spectroscopic Ellipsometry |
| title_full_unstemmed | Temperature Dependence of Optical Properties of MoS<sub>2</sub> and WS<sub>2</sub> Heterostructures Assessed by Spectroscopic Ellipsometry |
| title_short | Temperature Dependence of Optical Properties of MoS<sub>2</sub> and WS<sub>2</sub> Heterostructures Assessed by Spectroscopic Ellipsometry |
| title_sort | temperature dependence of optical properties of mos sub 2 sub and ws sub 2 sub heterostructures assessed by spectroscopic ellipsometry |
| topic | MoS<sub>2</sub> and WS<sub>2</sub> heterostructures spectroscopic ellipsometry dielectric function temperature dependence critical point exciton |
| url | https://www.mdpi.com/2079-4991/15/1/76 |
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