Exciton-dominant photoluminescence of MoS2 by a functionalized substrate

Eunji Ji, Kyungmin Yang, June Chul Shin, Youngbum Kim, Jin Woo Park, Jeongyong Kim, Gwan Hyoung Lee

Research output: Contribution to journalArticlepeer-review


Transition metal dichalcogenides (TMDs) have been considered as promising candidates for transparent and flexible optoelectronic devices owing to their large exciton binding energy and strong light-matter interaction. However, monolayer (1L) TMDs exhibited different intensities and spectra of photoluminescence (PL), and the characteristics of their electronic devices also differed in each study. This has been explained in terms of various defects in TMDs, such as vacancies and grain boundaries, and their surroundings, such as dielectric screening and charged impurities, which lead to non-radiative recombination of trions, low quantum yield (QY), and unexpected doping. However, it should be noted that the surface conditions of the substrate are also a critical factor in determining the properties of TMDs located on the substrate. Here, we demonstrate that the optical and electrical properties of 1L MoS2 are strongly influenced by the functionalized substrate. The PL of 1L MoS2 placed on the oxygen plasma-treated SiO2 substrate was highly p-doped owing to the functional groups of -OH on SiO2, resulting in a strong enhancement of PL by approximately 20 times. The PL QY of 1L MoS2 on plasma-treated SiO2 substrate increased by one order of magnitude. Surprisingly, the observed PL spectra show the suppression of non-radiative recombination by trions, thus the exciton-dominant PL led to a prolonged lifetime of MoS2 on the plasma-treated substrate. The MoS2 field-effect transistors fabricated on plasma-treated SiO2 also exhibited a large hysteresis in the transfer curve owing to charge trapping of the functional groups. Our study demonstrates that the functional groups on the substrate strongly affect the characteristics of 1L MoS2, which provides clues as to why MoS2 exfoliated on various substrates always exhibited different properties in previous studies.

Original languageEnglish
Pages (from-to)14106-14112
Number of pages7
Issue number38
Publication statusPublished - 2022 Sept 7

Bibliographical note

Funding Information:
This work was supported by the Creative-Pioneering Researchers Program through Seoul National University (SNU) and the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (NRF-2021R1A2C3014316 and NRF-2021M3F3A2A01037858).

Publisher Copyright:
© 2022 The Royal Society of Chemistry.

All Science Journal Classification (ASJC) codes

  • Materials Science(all)


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