Ultraviolet-Ozone Treatment: an Effective Method for Fine-Tuning Optical and Electrical Properties of Suspended and Substrate-Supported MoS₂

TY - JOUR

T1 - Ultraviolet-Ozone Treatment

T2 - an Effective Method for Fine-Tuning Optical and Electrical Properties of Suspended and Substrate-Supported MoS2

AU - Sarcan, Fahrettin

AU - Armstrong, Alex J.

AU - Bostan, Yusuf K.

AU - Kus, Esra

AU - McKenna, Keith P.

AU - Erol, Ayse

AU - Wang, Yue

N1 - © 2023 by the authors. Funding Information: This research was funded by the Royal Academy of Engineering (Research Fellowship awarded to Y.W., RF\201718\17131), the Scientific Research Projects Coordination Unit of Istanbul University (FBA-2023-39412, FBG-2022-38573, FBG-2021-37896), the Scientific and Technological Research Council of Turkey (TUBITAK) project (121F169), and EPSRC (EP/R029431 and EP/X035859).

PY - 2023/11/27

Y1 - 2023/11/27

N2 - Ultraviolet-ozone (UV-O3) treatment is a simple but effective technique for surface cleaning, surface sterilization, doping, and oxidation, and is applicable to a wide range of materials. In this study, we investigated how UV-O3 treatment affects the optical and electrical properties of molybdenum disulfide (MoS2), with and without the presence of a dielectric substrate. We performed detailed photoluminescence (PL) measurements on 1–7 layers of MoS2 with up to 8 min of UV-O3 exposure. Density functional theory (DFT) calculations were carried out to provide insight into oxygen-MoS2 interaction mechanisms. Our results showed that the influence of UV-O3 treatment on PL depends on whether the substrate is present, as well as the number of layers. Additionally, 4 min of UV-O3 treatment was found to be optimal to produce p-type MoS2, while maintaining above 80% of the PL intensity and the emission wavelength, compared to pristine flakes (intrinsically n-type). UV-O3 treatment for more than 6 min not only caused a reduction in the electron density but also deteriorated the hole-dominated transport. It is revealed that the substrate plays a critical role in the manipulation of the electrical and optical properties of MoS2, which should be considered in future device fabrication and applications.

AB - Ultraviolet-ozone (UV-O3) treatment is a simple but effective technique for surface cleaning, surface sterilization, doping, and oxidation, and is applicable to a wide range of materials. In this study, we investigated how UV-O3 treatment affects the optical and electrical properties of molybdenum disulfide (MoS2), with and without the presence of a dielectric substrate. We performed detailed photoluminescence (PL) measurements on 1–7 layers of MoS2 with up to 8 min of UV-O3 exposure. Density functional theory (DFT) calculations were carried out to provide insight into oxygen-MoS2 interaction mechanisms. Our results showed that the influence of UV-O3 treatment on PL depends on whether the substrate is present, as well as the number of layers. Additionally, 4 min of UV-O3 treatment was found to be optimal to produce p-type MoS2, while maintaining above 80% of the PL intensity and the emission wavelength, compared to pristine flakes (intrinsically n-type). UV-O3 treatment for more than 6 min not only caused a reduction in the electron density but also deteriorated the hole-dominated transport. It is revealed that the substrate plays a critical role in the manipulation of the electrical and optical properties of MoS2, which should be considered in future device fabrication and applications.

KW - density functional theory (DFT)

KW - doping

KW - field-effect transistor

KW - MoS

KW - photoluminescence

KW - surface treatment

KW - transition metal dichalcogenide

KW - ultraviolet-ozone (UV-O)

UR - http://www.scopus.com/inward/record.url?scp=85178924562&partnerID=8YFLogxK

U2 - 10.3390/nano13233034

DO - 10.3390/nano13233034

M3 - Article

AN - SCOPUS:85178924562

SN - 2079-4991

VL - 13

JO - Nanomaterials

JF - Nanomaterials

IS - 23

M1 - 3034

ER -