Optimizing the Morphology and Optical Properties of MoS<sub>2</sub> Using Different Substrate Placement: Numerical Simulation and Experimental Verification

The prerequisite for rapid and steady development of TMDC-based optoelectronic devices is high efficiency in materials preparation, which relies on a mature synthesis technique and optimized production conditions. Visualization based on numerical simulation, which illustrates the impact of growth pa...

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Main Authors: Feng Liao, Yuhan Zeng, Qingqing Xie, Yupeng Yang, Shuangyi Linghu, Li Liang, Zewen Zuo
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Crystals
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Online Access:https://www.mdpi.com/2073-4352/15/1/59
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author Feng Liao
Yuhan Zeng
Qingqing Xie
Yupeng Yang
Shuangyi Linghu
Li Liang
Zewen Zuo
author_facet Feng Liao
Yuhan Zeng
Qingqing Xie
Yupeng Yang
Shuangyi Linghu
Li Liang
Zewen Zuo
author_sort Feng Liao
collection DOAJ
description The prerequisite for rapid and steady development of TMDC-based optoelectronic devices is high efficiency in materials preparation, which relies on a mature synthesis technique and optimized production conditions. Visualization based on numerical simulation, which illustrates the impact of growth parameters on deposited products, is helpful to understand formation mechanisms and modify growth conditions. In this work, we construct two models with two different substrate placements, where the substrate is parallel or perpendicular to gas flow direction. The simulation results show more velocity distribution uniformity across a wider range from −1.4 cm to 1.4 cm for vertically placed (VP) compared to horizontally placed (HP) substrates. The calculated average velocities of 0.048, 0.053, 0.078, 0.137, and 0.391 cm/s along five different positions on the VP substrate are greater than the values of 0.027, 0.026, 0.025, 0.023, and 0.036 cm/s on the HP substrate. Comparing the precursor concentration distributions on both substrates, it is observed that the S molar concentration gradient on both substrates is negligible and the uniform Mo molar concentrations from z = −1.4 cm to 2.0 cm on the VP substrate ensure minimal change in the S/Mo ratio, which contributes to forming single-morphology domains. Furthermore, increasing the distance between the precursor inlets and the VP substrate decreases the amount of molecules on the substrate surface, achieving near-stoichiometry and promoting monolayer deposition. This is verified by the experimental result, which showed gentle morphological transformation on the VP substrate from a truncated triangle to a hexagon, and then back to a truncated triangle. By contrast, the multi-morphology and thickness of MoS<sub>2</sub> on the HP substrate result from the complex Mo concentration along the flow direction. Moreover, PL intensities of the MoS<sub>2</sub> domains deposited on the VP substrate are enhanced by 11.9-fold compared to the average intensity on the HP substrate. This result indicates the MoS<sub>2</sub> grown on the VP substrate has less intrinsic defects than that grown on the HP substrate. The combination of numerical simulation with experimental methods facilitates the visualization of invisible growth conditions, which provides effective guidance for using simulation results for other TMDC materials.
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spelling doaj-art-35556c82a75447fab5fecd635242e7542025-01-24T13:28:09ZengMDPI AGCrystals2073-43522025-01-011515910.3390/cryst15010059Optimizing the Morphology and Optical Properties of MoS<sub>2</sub> Using Different Substrate Placement: Numerical Simulation and Experimental VerificationFeng Liao0Yuhan Zeng1Qingqing Xie2Yupeng Yang3Shuangyi Linghu4Li Liang5Zewen Zuo6School of Physics and Electronic Information, Anhui Normal University, Wuhu 241003, ChinaSchool of Physics and Electronic Information, Anhui Normal University, Wuhu 241003, ChinaSchool of Physics and Electronic Information, Anhui Normal University, Wuhu 241003, ChinaSchool of Physics and Electronic Information, Anhui Normal University, Wuhu 241003, ChinaCollege of Physics, Guizhou University, Guiyang 550025, ChinaSchool of Physics and Electronic Information, Anhui Normal University, Wuhu 241003, ChinaSchool of Physics and Electronic Information, Anhui Normal University, Wuhu 241003, ChinaThe prerequisite for rapid and steady development of TMDC-based optoelectronic devices is high efficiency in materials preparation, which relies on a mature synthesis technique and optimized production conditions. Visualization based on numerical simulation, which illustrates the impact of growth parameters on deposited products, is helpful to understand formation mechanisms and modify growth conditions. In this work, we construct two models with two different substrate placements, where the substrate is parallel or perpendicular to gas flow direction. The simulation results show more velocity distribution uniformity across a wider range from −1.4 cm to 1.4 cm for vertically placed (VP) compared to horizontally placed (HP) substrates. The calculated average velocities of 0.048, 0.053, 0.078, 0.137, and 0.391 cm/s along five different positions on the VP substrate are greater than the values of 0.027, 0.026, 0.025, 0.023, and 0.036 cm/s on the HP substrate. Comparing the precursor concentration distributions on both substrates, it is observed that the S molar concentration gradient on both substrates is negligible and the uniform Mo molar concentrations from z = −1.4 cm to 2.0 cm on the VP substrate ensure minimal change in the S/Mo ratio, which contributes to forming single-morphology domains. Furthermore, increasing the distance between the precursor inlets and the VP substrate decreases the amount of molecules on the substrate surface, achieving near-stoichiometry and promoting monolayer deposition. This is verified by the experimental result, which showed gentle morphological transformation on the VP substrate from a truncated triangle to a hexagon, and then back to a truncated triangle. By contrast, the multi-morphology and thickness of MoS<sub>2</sub> on the HP substrate result from the complex Mo concentration along the flow direction. Moreover, PL intensities of the MoS<sub>2</sub> domains deposited on the VP substrate are enhanced by 11.9-fold compared to the average intensity on the HP substrate. This result indicates the MoS<sub>2</sub> grown on the VP substrate has less intrinsic defects than that grown on the HP substrate. The combination of numerical simulation with experimental methods facilitates the visualization of invisible growth conditions, which provides effective guidance for using simulation results for other TMDC materials.https://www.mdpi.com/2073-4352/15/1/59TMDCssubstrate placementvelocitymolar concentrationPL enhancement
spellingShingle Feng Liao
Yuhan Zeng
Qingqing Xie
Yupeng Yang
Shuangyi Linghu
Li Liang
Zewen Zuo
Optimizing the Morphology and Optical Properties of MoS<sub>2</sub> Using Different Substrate Placement: Numerical Simulation and Experimental Verification
Crystals
TMDCs
substrate placement
velocity
molar concentration
PL enhancement
title Optimizing the Morphology and Optical Properties of MoS<sub>2</sub> Using Different Substrate Placement: Numerical Simulation and Experimental Verification
title_full Optimizing the Morphology and Optical Properties of MoS<sub>2</sub> Using Different Substrate Placement: Numerical Simulation and Experimental Verification
title_fullStr Optimizing the Morphology and Optical Properties of MoS<sub>2</sub> Using Different Substrate Placement: Numerical Simulation and Experimental Verification
title_full_unstemmed Optimizing the Morphology and Optical Properties of MoS<sub>2</sub> Using Different Substrate Placement: Numerical Simulation and Experimental Verification
title_short Optimizing the Morphology and Optical Properties of MoS<sub>2</sub> Using Different Substrate Placement: Numerical Simulation and Experimental Verification
title_sort optimizing the morphology and optical properties of mos sub 2 sub using different substrate placement numerical simulation and experimental verification
topic TMDCs
substrate placement
velocity
molar concentration
PL enhancement
url https://www.mdpi.com/2073-4352/15/1/59
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AT yuhanzeng optimizingthemorphologyandopticalpropertiesofmossub2subusingdifferentsubstrateplacementnumericalsimulationandexperimentalverification
AT qingqingxie optimizingthemorphologyandopticalpropertiesofmossub2subusingdifferentsubstrateplacementnumericalsimulationandexperimentalverification
AT yupengyang optimizingthemorphologyandopticalpropertiesofmossub2subusingdifferentsubstrateplacementnumericalsimulationandexperimentalverification
AT shuangyilinghu optimizingthemorphologyandopticalpropertiesofmossub2subusingdifferentsubstrateplacementnumericalsimulationandexperimentalverification
AT liliang optimizingthemorphologyandopticalpropertiesofmossub2subusingdifferentsubstrateplacementnumericalsimulationandexperimentalverification
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