Defects activated photoluminescence in two-dimensional semiconductors: interplay between bound, charged, and free excitons
Name
Tongay-2013-Defects activated pholuminescence.pdf
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Author(s)
Tongay, Sefaattin
Suh, Joonki
Ataca, Can
Fan, Wen
Luce, Alexander
Kang, Jeong Seuk
Liu, Jonathan
Ko, Changhyun
Raghunathanan, Rajamani
Zhou, Jian
Date Issued
September 2013
Journal
Scientific Reports
Publisher
Nature Publishing Group
Citation
Tongay, Sefaattin, Joonki Suh, Can Ataca, Wen Fan, Alexander Luce, Jeong Seuk Kang, Jonathan Liu, et al. “Defects Activated Photoluminescence in Two-Dimensional Semiconductors: Interplay Between Bound, Charged, and Free Excitons.” Sci. Rep. 3 (September 13, 2013).
Version
Final published version
Abstract
Point defects in semiconductors can trap free charge carriers and localize excitons. The interaction between these defects and charge carriers becomes stronger at reduced dimensionalities, and is expected to greatly influence physical properties of the hosting material. We investigated effects of anion vacancies in monolayer transition metal dichalcogenides as two-dimensional (2D) semiconductors where the vacancies density is controlled by α-particle irradiation or thermal-annealing. We found a new, sub-bandgap emission peak as well as increase in overall photoluminescence intensity as a result of the vacancy generation. Interestingly, these effects are absent when measured in vacuum. We conclude that in opposite to conventional wisdom, optical quality at room temperature cannot be used as criteria to assess crystal quality of the 2D semiconductors. Our results not only shed light on defect and exciton physics of 2D semiconductors, but also offer a new route toward tailoring optical properties of 2D semiconductors by defect engineering.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
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Creative Commons Attribution 3.0
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DOI of Published Version
https://doi.org/10.1038/srep02657
