title: Charge-transfer-based gas sensing using atomic-layer MoS2.
abstract: Two-dimensional (2D) molybdenum disulphide (MoS2) atomic layers have a strong potential to be used as 2D electronic sensor components. However, intrinsic synthesis challenges have made this task difficult. In addition, the detection mechanisms for gas molecules are not fully understood. Here, we report a high-performance gas sensor constructed using atomic-layered MoS2 synthesised by chemical vapour deposition (CVD). A highly sensitive and selective gas sensor based on the CVD-synthesised MoS2 was developed. In situ photoluminescence characterisation revealed the charge transfer mechanism between the gas molecules and MoS2, which was validated by theoretical calculations. First-principles density functional theory calculations indicated that NO2 and NH3 molecules have negative adsorption energies (i.e., the adsorption processes are exothermic). Thus, NO2 and NH3 molecules are likely to adsorb onto the surface of the MoS2. The in situ PL characterisation of the changes in the peaks corresponding to charged trions and neutral excitons via gas adsorption processes was used to elucidate the mechanisms of charge transfer between the MoS2 and the gas molecules.
authors.affiliation: Advanced Functional Thin Films Department, Surface Technology Division, Korea Institute of Materials Science (KIMS), 797 Changwondaero, Sungsan-Gu, Changwon, Gyeongnam 642-831, Republic of Korea.
authors.forename: Byungjin
authors.initials: B
authors.lastname: Cho
authors.affiliation: Advanced Functional Thin Films Department, Surface Technology Division, Korea Institute of Materials Science (KIMS), 797 Changwondaero, Sungsan-Gu, Changwon, Gyeongnam 642-831, Republic of Korea.
authors.forename: Myung Gwan
authors.initials: MG
authors.lastname: Hahm
authors.affiliation: Advanced Characterization and Analysis Group, Korea Institute of Materials Science (KIMS), 797 Changwondaero, Sungsan-Gu, Changwon, Gyeongnam 642-831, Republic of Korea.
authors.forename: Minseok
authors.initials: M
authors.lastname: Choi
authors.affiliation: School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Buk-Gu, Gwangju 500-712, Republic of Korea.
authors.forename: Jongwon
authors.initials: J
authors.lastname: Yoon
authors.affiliation: Advanced Functional Thin Films Department, Surface Technology Division, Korea Institute of Materials Science (KIMS), 797 Changwondaero, Sungsan-Gu, Changwon, Gyeongnam 642-831, Republic of Korea.
authors.forename: Ah Ra
authors.initials: AR
authors.lastname: Kim
authors.affiliation: Advanced Functional Thin Films Department, Surface Technology Division, Korea Institute of Materials Science (KIMS), 797 Changwondaero, Sungsan-Gu, Changwon, Gyeongnam 642-831, Republic of Korea.
authors.forename: Young-Joo
authors.initials: YJ
authors.lastname: Lee
authors.affiliation: Advanced Functional Thin Films Department, Surface Technology Division, Korea Institute of Materials Science (KIMS), 797 Changwondaero, Sungsan-Gu, Changwon, Gyeongnam 642-831, Republic of Korea.
authors.forename: Sung-Gyu
authors.initials: SG
authors.lastname: Park
authors.affiliation: Advanced Functional Thin Films Department, Surface Technology Division, Korea Institute of Materials Science (KIMS), 797 Changwondaero, Sungsan-Gu, Changwon, Gyeongnam 642-831, Republic of Korea.
authors.forename: Jung-Dae
authors.initials: JD
authors.lastname: Kwon
authors.affiliation: Advanced Functional Thin Films Department, Surface Technology Division, Korea Institute of Materials Science (KIMS), 797 Changwondaero, Sungsan-Gu, Changwon, Gyeongnam 642-831, Republic of Korea.
authors.forename: Chang Su
authors.initials: CS
authors.lastname: Kim
authors.affiliation: Advanced Functional Thin Films Department, Surface Technology Division, Korea Institute of Materials Science (KIMS), 797 Changwondaero, Sungsan-Gu, Changwon, Gyeongnam 642-831, Republic of Korea.
authors.forename: Myungkwan
authors.initials: M
authors.lastname: Song
authors.affiliation: Electrochemistry Department, Korea Institute of Materials Science (KIMS), 797 Changwondaero, Sungsan-Gu, Changwon, Gyeongnam 642-831, Republic of Korea.
authors.forename: Yongsoo
authors.initials: Y
authors.lastname: Jeong
authors.affiliation: Advanced Functional Thin Films Department, Surface Technology Division, Korea Institute of Materials Science (KIMS), 797 Changwondaero, Sungsan-Gu, Changwon, Gyeongnam 642-831, Republic of Korea.
authors.forename: Kee-Seok
authors.initials: KS
authors.lastname: Nam
authors.affiliation: Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States.
authors.forename: Sangchul
authors.initials: S
authors.lastname: Lee
authors.affiliation: School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Buk-Gu, Gwangju 500-712, Republic of Korea.
authors.forename: Tae Jin
authors.initials: TJ
authors.lastname: Yoo
authors.affiliation: Cambridge Graphene Center, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, United Kingdom.
authors.forename: Chang Goo
authors.initials: CG
authors.lastname: Kang
authors.affiliation: School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Buk-Gu, Gwangju 500-712, Republic of Korea.
authors.forename: Byoung Hun
authors.initials: BH
authors.lastname: Lee
authors.affiliation: School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Buk-Gu, Gwangju 500-712, Republic of Korea.
authors.forename: Heung Cho
authors.initials: HC
authors.lastname: Ko
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University, 6100 Main Street, Houston, Texas 77005, USA.
authors.forename: Pulickel M
authors.initials: PM
authors.lastname: Ajayan
authors.affiliation: Advanced Functional Thin Films Department, Surface Technology Division, Korea Institute of Materials Science (KIMS), 797 Changwondaero, Sungsan-Gu, Changwon, Gyeongnam 642-831, Republic of Korea.
authors.forename: Dong-Ho
authors.initials: DH
authors.lastname: Kim