Effect of Sulfurization Temperature on RF Sputtered MoS2 Thin Film

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

Copyright © IAAM-VBRI Press

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.