Effect of Sulfurization Temperature on RF Sputtered MoS2 Thin Film

V. Thiruvengadam1, Braj Bhusan Singh1, Palash Kumar Manna1, Subhankar Bedanta1,2,*

1Laboratory for Nanomagnetism and Magnetic Materials (LNMM), School of Physical Sciences, National Institute of Science Education and Research (NISER), HBNI, P.O. Bhimpur Padanpur, Via Jatni, 752050, India

2Center for Interdisciplinary Sciences (CIS), National Institute of Science Education and Research (NISER), HBNI, P.O.  Bhimpur Padanpur, Via Jatni, 752050, India

Adv. Mater. Lett., 2021, 12 (2), 21021603

DOI: 10.5185/amlett.2021.021603

Publication Date (Web): Dec 16, 2020

E-mail: sbedanta@niser.ac.in

Abstract


Molybdenum disulfide (MoS2) is one among the transition-metal dichalcogenide (TMD) family which exhibits exotic physical properties at their mono-layer limit. We report a facile way to fabricate stoichiometric, crystalline and star shaped MoS2 film. In this work, ultra-thin MoS2 films were fabricated by two step process (i) RF sputtering of MoS2 target followed by (ii) sulfurization to improve stoichiometry and crystallinity. In order to study the effect of sulfurization temperature on sputtered MoS2, sulfurization has been performed at five different temperatures - 700, 750, 775, 800 and 825°C. Surface morphology of as sputtered and sulfurized MoS2 films were characterized using optical and scanning electron microscopes. Crystallinity and layer thickness of the fabricated MoS2 films were estimated by using Laser Raman spectroscopy. These results confirm that as sputtered MoS2 films are discontinuous, amorphous in nature and it crystalizes into a layered structure during sulfurization at temperature ≥ 750°C. It was observed that at sulfurization temperature of 800°C, the nucleated crystallites well grown into a star shaped crystalline MoS2 with their thickness vary between 2 and 3 mono-layers. These star shapes can provide more surface area/edges that can be exploited to enhance the efficiency of gas sensors.

Keywords

MoS2, dichalcogenides, sputtering, sulfurization, Raman spectrosopy.

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