High mobility field-effect transistors based on MoS2crystals grown by the flux method

Vilas Patil; Jihyun Kim; Khushabu Agrawal; Tuson Park; Junsin Yi; Nobuyuki Aoki; Kenji Watanabe; Takashi Taniguchi; Gil-Ho Kim

doi:10.1088/1361-6528/abf6f1

High mobility field-effect transistors based on MoS₂crystals grown by the flux method

Nanotechnology. 2021 May 17;32(32). doi: 10.1088/1361-6528/abf6f1.

Authors

Vilas Patil^{1

2}, Jihyun Kim³, Khushabu Agrawal¹, Tuson Park³, Junsin Yi¹, Nobuyuki Aoki⁴, Kenji Watanabe⁵, Takashi Taniguchi⁶, Gil-Ho Kim^{1

7}

Affiliations

¹ School of Electronic and Electrical Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea.
² Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India.
³ Centre for Quantum Materials and Superconductivity (CQMS), Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea.
⁴ Department of Materials Science, Chiba University, Chiba 263-8522, Japan.
⁵ Research Centre for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
⁶ International Centre for Materials Nano-Architectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
⁷ Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, Republic of Korea.

PMID: 33845468
DOI: 10.1088/1361-6528/abf6f1

Abstract

Two-dimensional (2D) molybdenum disulphide (MoS₂) transition metal dichalcogenides (TMDs) have great potential for use in optical and electronic device applications; however, the performance of MoS₂is limited by its crystal quality, which serves as a measure of the defects and grain boundaries in the grown material. Therefore, the high-quality growth of MoS₂crystals continues to be a critical issue. In this context, we propose the formation of high-quality MoS₂crystals via the flux method. The resulting electrical properties demonstrate the significant impact of crystal morphology on the performance of MoS₂field-effect transistors. MoS₂made with a relatively higher concentration of sulphur (a molar ratio of 2.2) and at a cooling rate of 2.5 °C h^-1yielded good quality and optimally sized crystals. The room-temperature and low-temperature (77 K) electrical transport properties of MoS₂field-effect transistors (FETs) were studied in detail, with and without the use of a hexagonal boron nitride (h-BN) dielectric to address the mobility degradation issue due to scattering at the SiO₂/2D material interface. A maximum field-effect mobility of 113 cm²V^-1s^-1was achieved at 77 K for the MoS₂/h-BN FET following high-quality crystal formation by the flux method. Our results confirm the achievement of large-scale high-quality crystal growth with reduced defect density using the flux method and are key to achieving higher mobility in MoS₂FET devices in parallel with commercially accessible MoS₂crystals.

Keywords: Field-effect transistor; Flux method; MoS2; hexagonal boron nitride (h-BN).