In this work synthesis of layered molybdenum sulphide (MoS2) through a temperature-controlled thermal evaporation approach is reported. Simultaneous co-evaporation of molybdenum trioxide (MoO3) and sulphur in an argon environment is employed. The as-deposited thin films are characterized by diffraction and microscopy

Balendhran, S

Bhargava, S

Bhaskaran, M

Ippolito, S

Kalantar Zadeh, K

Kats, E

Ou, J

Sriram, S

Vasic, Z

Zhuiykov, S

RMIT Research Repository

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Balendhran, S, Ou, J, Bhaskaran, M, Sriram, S, Ippolito, S, Vasic, Z, Kats, E, Bhargava, S,
Zhuiykov, S and Kalantar Zadeh, K 2012, 'Facile synthesis of layered hexagonal MoS2', in
Brendan Griffin, Lorenzo Faraone, Mariusz Martyniuk (ed.) Proceedings of the APMC 10 /
ICONN 2012 / ACMM 22, Perth, Australia, 5-9 February 2012, pp. 82-1-82-2.
http://researchbank.rmit.edu.au/view/rmit:23893
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http://www.microscopy.org.au/ACMM-22/
Facile Synthesis of Layered Hexagonal MoS2 
S. Balendhran1 *, J. Z. Ou1, M. Bhaskaran1, S. Sriram1, S. Ippolito2, Z. Vasic3, E. Kats4, 
S. Bhargava2, S. Zhuiykov2, and K. Kalantar-zadeh1 
1
 School of Electrical and Computer Engineering, RMIT University, Melbourne, VIC, Australia  
2
School of Applied Sciences, RMIT University, Melbourne, VIC, Australia 
3
Melbourne Centre for Nano Fabrication, Clayton, VIC, Australia 
2 
Material Science and Engineering Division, Commonwealth Scientific Industrial Research Organisation 
(CSIRO), Melbourne, VIC, Australia 
*Corresponding author: Email shiva.balendhran@rmit.edu.au  
Abstract: In this work synthesis of layered molybdenum sulphide (MoS2) through a tem-
perature-controlled thermal evaporation approach is reported. Simultaneous 
co-evaporation of molybdenum trioxide (MoO3) and sulphur in an argon environment is 
employed.  The as-deposited thin films are characterized by diffraction and microscopy. 
Introduction: MoS2 has attracted particular interest in the research field of two dimen-
sional (2D) semiconductor materials due to its intrinsic narrow band gap and layered na-
ture. The fundamental layer of MoS2 is composed of a layer of molybdenum (Mo) atoms 
sandwiched between two layers of sulphur (S) atoms. These layers are held together by 
weak van der Waals (Fig. 1a). In recent years, the enhancement in the carrier mobility of a 
single atomic layer of MoS2 has been demonstrated by Kis et al. [1]. In addition, the 
change in band gap from indirect to direct at 2D levels while exhibiting significant photolu-
minescence has also been reported [2]. In achieving such desirable properties, synthesis 
of layered MoS2 is crucial. 
MoS2 can be synthesized in various morphologies using a wide range of methods. Some 
of the less complicated methods are thermal decomposition of thiomolybdate precursors 
[3] and chemical reaction between Mo and S based compounds [4]. Still these methods 
require harsh environments and hazardous materials [3,4]. Other methods require complex 
setups and are conducted over a long period of time [4,5]. Hence, a better and simpler al-
ternative process is highly desirable. Thermal evaporation is considered to be a simpler 
technique, but evaporation of MoS2 is disregarded as an alternative since the evaporation 
temperature of MoS2 is 1375 °C. To overcome such high temperature barrier thermal 
evaporation MoO3 which has a comparatively lower evaporation temperature of 775 °C 
along with S was employed. 
 
Experimental: MoO3 powder and sulphur were placed in the quartz tube as shown in 
Fig. 1a. Initially the centre of the tube was offset from the centre of the furnace. The fur-
nace temperature was increased at a rate of 20 °C/min under a constant argon flow of 
200 sccm. When the temperature reached 750 °C, the centre of the quartz tube was 
aligned with the centre of the furnace. The furnace was further heated up to a maximum 
temperature and annealed for certain duration before cooling down. Three cases of differ-
ent annealing temperatures and duration are presented: (I) 775 °C for 60 mins, (II) 830 °C 
for 60 mins and (III) 830 °C for 180 mins. Thin films were deposited on the quartz sub-
strates along the downstream of the argon flow. 
 
Results and Discussion: Figure 1b illustrates the X-ray diffraction (XRD) patterns ac-
quired of the samples obtained at different annealing conditions. The samples obtained at 
lower temperatures of 775 °C prove to be dominantly molybdenum dioxide (MoO2) (ICDD 
Card No.: 76-1807). Increasing the annealing temperature to 830 °C seems to have pro-
duced a combinational growth of crystalline MoS2 and MoO2. Further increasing the an-
nealing duration from 60 mins to 180 mins at 830 °C reveal dominant growth of crystalline 
layered MoS2 (ICDD Card No.: 77-1716). These results elucidate the conversion process 
of MoO3 being reduced to MoO2 and further annealing in S resulting in layered MoS2 
growth. Atomic force microscopy (AFM) thickness analysis reveals the layered nature of 
these MoS2 flakes (Fig. 1c). Furthermore, scanning electron microscopy (SEM) images of 
the thin film obtained at the annealing conditions of 830 °C for 180 mins (Fig. 1d) shows 
the growth morphology of the layered crystallites. 
 
Conclusions: In summary, we have demonstrated the synthesis of high purity, layered 
MoS2 through a simple, controllable method of thermal evaporation. This technique can be 
applied in standard fabrication facilities and does not require complex experimental setups. 
In addition it proves to be an effective and less hazardous alternative to the current selec-
tion of processes. The crystalline, layered structure of the MoS2 has been verified by XRD, 
AFM, and SEM analysis. 
 
References 
[1] B. Radisavljevic, A. Radenovic, J. Brivio, V. Giacometti, and A. Kis, “Single-layer MoS2 transistors,” Nat. 
Nanotechnol., vol. 6, pp.147–150, 2011. 
[2] A. Splendiani, L. Sun, Y. B. Zhang, T. S. Li, J. Kim, C. Y. Chim, G. Galli, and F. Wang, “Emerging 
photoluminescence in monolayer MoS2,” Nano Lett., vol. 10, pp. 1271–1275, 2010. 
[3] H. Farag, A. N. A. El-Hendawy, K. Sakanishi, M. Kishida, and I. Mochida, “Catalytic activity of 
synthesized nanosized molybdenum disulfide for the hydrodesulfurization of bibenzothiophene: Effect of 
H2S partial pressure”, Appl. Catal. B Environ., vol. 91, pp. 189–197, 2009. 
[4] X. Y. Chen, X. Wang, Z. H. Wang, W. C. Yu, and Y. T. Qian, “Direct sulfidization synthesis of high-quality 
binary sulfides (WS2, MoS2, and V5S8) from the respective oxides,” Mater. Chem. Phys., vol. 87, pp. 327–
331, 2004. 
[5] M. Virsek, M. Krause, A. Kolitsch, and M. Remskar, “Raman characterization of MoS2 microtube,” Phys. 
Stat. Sol. B, vol. 246, pp. 2782–2785, 2009. 
 
 
 
 
 
 
 
 
 
 
 
Fig. 1. (a) Experimental setup: 1. Sulphur powder, 2. MoO3 nano powder and 
3. Quartz substrates for thin film deposition; (b) XRD patterns of thin films annealed 
at I. 775 °C for 60 mins, II. 830 °C for 60 mins and III. 830 °C for 180 mins (peaks 
correspond to [*] MoS2, [¤] MoO2 and [×] MoO3); (c) AFM thickness profile of a ob-
tained MoS2 flake;  and (d) SEM images of the thin films annealed at 830 °C for 
180 mins. 


Facile synthesis of layered hexagonal MoS2

Facile synthesis of layered hexagonal MoS2

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