Structural And Optical Properties Of Molybdenum Disulfide Thin Films Grown By Thermal Vapour Sulfurization
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Date
2019-05
Authors
Tan, Aik Leng
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Publisher
Universiti Sains Malaysia
Abstract
In this work, the molybdenum disulfide (MoS2) thin films were grown by using thermal vapour sulfurization (TVS) technique. Spin coating method was used to deposit MoS-based films due to its ability to coat flat and homogeneous films. The dual source precursor (DSP) approach is applied for the precursor solution preparation prior to the spin coating process. Several molybdenum oxide compounds were present in the intermediate product. These compounds were formed by the sequence of molybdenum oxide (MoO3) → intermediate molybdenum oxide (Mo4O11) → molybdenum dioxide (MoO2). However, none of the Mo-O and Mo-S related bondings were detected due to the domination of infrared (IR) characteristics from ethylenediamine solvent. Next, the growth optimizing studies were first conducted by using silicon substrate. The sulfurization duration and temperature of 40 min and 850 °C were obtained as the optimum sulfurization conditions for the TVS technique. Also, sulfurization process was the crucial process in growing the MoS2 thin films and the early formation of Mo-S started at second stage of thermal processes. Subsequently, the optimum sulfurization conditions were used to study the growth of MoS2 thin films on different substrates. Single crystalline substrate with the hexagonal lattice system (sapphire) enhanced the growth of MoS2 thin films. This is due to the lower lattice mismatch and similar crystal symmetry which smoothen the surface nature of MoS2 thin films.
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Keywords
Molybdenum Disulfide Thin Films , Thermal Vapour Sulfurization