自發現以來，二硫化鉬（MoS2）已成為一種非凡的 2D 分層材料。除了作為石墨烯的合適替代品之外， MoS2 還具有廣泛的新物理和化學特性，例如 2D 層之間的弱范德華力（產生低摩擦係數） [18]，電導率為 10-4 Ω-1 cm-1 [6] 隨著光子學和光伏質量的提高，它成為化學反應的催化劑。此外，這種獨特的化 合物在插入其他元素時具有良好的可調特性。對我們的行業有很多重要影響 的應用，例如氫沉澱反應（HER），可以從 MoS2 的性能大幅提升中受益。但是，當期望將元素插入其中時，必須完全調查 MoS2 的內在缺陷。在這裡，我們提出了一個詳細的缺陷研究，以及 MoS2對高定向熱解石墨（HOPG）基板的電壓依賴性，涉及掃描隧道顯微鏡（STM）特性。

Molybdenum disulfide (MoS2) has emerged as an extraordinary 2D layered material since its discovery. In addition to its potential to be a suitable replacement for graphene, MoS2 possesses a wide range of novel physical as well as chemical properties such as a weak Van der Waals force between 2D layers of atoms (leading to low coefficient of friction) [18], an electrical conductivity of 10-4Ω-1cm-1 [6], owning an improved photonics and photovoltaics quality, being a catalyst for chemical reactions, etc.. Furthermore, this distinctive compound displays fabulous tunable properties when being intercalated with other elements. Several strongly impacting applications for our industries, e.g. hydrogen evolution reaction (HER), benefit from such a huge enhancement in performance of MoS2. Hence, comprehensive investigations of intrinsic defects of MoS2 must be performed in anticipation of intercalating elements into it. However, while investigating these defects, a strong voltage dependent characteristic of MoS2 monolayer is observed. Here, we present a detailed voltage dependent study of MoS2 monolayer on highly oriented pyrolyticgraphite (HOPG) substrate involving scanning tunneling microscope (STM).

1 Introduction 5
2 Scanning Tunneling Microscope (STM) { A powerful instrument
for surface analysis of materials 7
2.1 Brief overview of the scanning tunneling microscope and its working
principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 The work function (φ) . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.3 Tunneling phenomenon and theory aspect of Scanning tunneling
spectroscopy (STS) . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.2 One-dimensional case (Bardeen theory) . . . . . . . . . . . . 11
2.3.3 Three-dimensional case (modified Bardeen theory) . . . . . . 14
2.3.4 Accuracy of approximation . . . . . . . . . . . . . . . . . . . 16
2.3.5 General tip . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.3.6 The Tersoff-Hamann model (the s-wave tip model) . . . . . 17
2.4 Working principles of the STM . . . . . . . . . . . . . . . . . . . . 18
3 Constitution of our STM 19
3.1 STM from RHK Technology . . . . . . . . . . . . . . . . . . . . . . 19
3.2 Preparation chamber . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.2.1 Heating stage . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.2.2 Quartz Crystal Microbalance (QCM) . . . . . . . . . . . . . 25
3.2.3 Molecular evaporator . . . . . . . . . . . . . . . . . . . . . . 27
3.3 STM chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.3.1 Piezoelectric Scanner . . . . . . . . . . . . . . . . . . . . . . 29
3.3.2 Coarse Positioner (coarse approach) . . . . . . . . . . . . . . 33
3.3.3 The X-Y table . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.4 Imaging process and atomic resolution . . . . . . . . . . . . . . . . 36
3.5 Tip, sample and sample labelling . . . . . . . . . . . . . . . . . . . 38
4 Vacuum pumps, electronics and software 40
4.1 Vacuum pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.1.1 Rotary pump . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.1.2 Turbomolecular pump . . . . . . . . . . . . . . . . . . . . . 42
4.1.3 Sputter-ion pumps . . . . . . . . . . . . . . . . . . . . . . . 43
4.1.4 Titanium sublimation pump . . . . . . . . . . . . . . . . . . 47
4.2 Electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
4.2.1 Model SR830 DSP lock-in Amplifier . . . . . . . . . . . . . . 47
4.2.2 Piezo Motor Controller (PMC) and SPM 100 . . . . . . . . 48
4.2.3 Convectron gauge and ion gauge . . . . . . . . . . . . . . . . 49
4.2.4 Residual gas analyzer (RGA) . . . . . . . . . . . . . . . . . 51
4.3 XPM Pro, WSxM and MATLAB . . . . . . . . . . . . . . . . . . . 53
5 Literature review 55
5.1 Temperature influence on the growth of MoS2 . . . . . . . . . . . . 56
5.2 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
5.3 MoS2 on Highly Oriented Pyrolytic Graphite (HOPG) . . . . . . . 61
5.4 Crystalline phases of MoS2, point defects and grain boundaries . . . 65
5.4.1 Crystalline phases of MoS2 . . . . . . . . . . . . . . . . . . . 65
5.4.2 Point defects and grain boundaries . . . . . . . . . . . . . . 68
6 Experimental result and discussion 70
6.1 Monolayer and multilayer MoS2 on Highly Oriented Pyrolytic Graphite
(HOPG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6.2 Voltage dependence result . . . . . . . . . . . . . . . . . . . . . . . 75
6.3 STS result . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
6.4 Defects and vacancies . . . . . . . . . . . . . . . . . . . . . . . . . . 83
6.5 Handling data with MATLAB . . . . . . . . . . . . . . . . . . . . . 85
7 Conclusion 87
8 Appendix 88
8.1 MATLAB Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
8.1.1 Reading \.SM4" file . . . . . . . . . . . . . . . . . . . . . . . 88
8.1.2 Interface (this code is saved under the name ’stm.m’) . . . . 102
8.1.3 Plotting STM image . . . . . . . . . . . . . . . . . . . . . . 106
8.1.4 Plotting STS graph . . . . . . . . . . . . . . . . . . . . . . . 107
8.1.5 Main code . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
Bibliography 109

[1] Imam Abdul Rahman and Acep Purqon. \First Principles Study of Molybdenum Disulfide Electronic Structure". In: Journal of Physics: Conference
Series 877 (July 2017), p. 012026. doi: 10.1088/1742-6596/877/1/012026.
[2] Rafik Addou, Luigi Colombo, and Robert Wallace. \Surface Defects on Natural MoS2". In: ACS applied materials & interfaces 7 (May 2015). doi:
10.1021/acsami.5b01778.
[3] Rafik Addou, Luigi Colombo, and Robert Wallace. \Surface Defects on Natural MoS2". In: ACS applied materials & interfaces 7 (May 2015). doi:
10.1021/acsami.5b01778.
[4] Agilent Sputter Ion Pumps - A 60-year history. https://www.agilent.com/
cs/library/periodicals/public/Agilent-Ion-Pump-History.pdf.
[5] G.B. Arfken, H.J. Weber, and F.E. Harris. Mathematical Methods for Physicists. Elsevier, 2005. isbn: 9780120598762. url: https://books.google.
com.tw/books?id=f3aCnXWV1CcC.
[6] O. El Beqqali et al. \Electrical properties of molybdenum disulfide MoS2.
Experimental study and density functional calculation results". In: Synthetic
Metals 90.3 (1997). Molecular Materials Applications to Sensors and Optoelectric Devices, pp. 165{172. issn: 0379-6779. doi: https://doi.org/10.
1016/S0379-6779(98)80002-7. url: http://www.sciencedirect.com/
science/article/pii/S0379677998800027.
[7] G. Binnig et al. \Surface Studies by Scanning Tunneling Microscopy". In:
Phys. Rev. Lett. 49 (1 July 1982), pp. 57{61. doi: 10.1103/PhysRevLett.
49.57. url: https://link.aps.org/doi/10.1103/PhysRevLett.49.57.
[8] G. Binnig et al. \Tunneling through a controllable vacuum gap". In: Applied
Physics Letters 40.2 (1982), pp. 178{180. doi: 10.1063/1.92999. eprint: https://doi.org/10.1063/1.92999. url: https://doi.org/10.1063/1. 92999.
[9] Matthias B¨ohringer et al. \Corrugation reversal in scanning tunneling microscope images of organic molecules". In: Physical Review B 57 (Feb. 1998). doi: 10.1103/PhysRevB.57.4081.
[10] caldarolamartin/read sm4 files. https://github.com/caldarolamartin/read_sm4_files.
[11] C. Julian Chen. \Corrugation reversal in scanning tunneling microscopy". In: Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena 12.3 (1994), pp. 2193{2199. doi: 10.1116/1.587739. eprint: https://avs.scitation.org/doi/
pdf/10.1116/1.587739. url: https://avs.scitation.org/doi/abs/10.
1116/1.587739.
[12] C.J. Chen. Introduction to Scanning Tunneling Microscopy. Introduction to
Scanning Tunneling Microscopy. OUP Oxford, 2008. isbn: 9780199211500.
url: https://books.google.com.tw/books?id=mDVCAQAAIAAJ.
[13] Julian Chen et al. \Three-electrode self-actuating self-sensing quartz cantilever: Design, analysis, and experimental verification". In: Review of Scientific Instruments 81 (June 2010), pp. 053702{053702. doi: 10.1063/1.
3407507.
[14] Yan Chen et al. \Tuning Electronic Structure of Single Layer MoS2 through
Defect and Interface Engineering". In: ACS Nano 12 (Feb. 2018). doi: 10.
1021/acsnano.7b08418.
[15] Ada Della Pia and Giovanni Costantini. \Scanning Tunneling Microscopy".
In: Surface Science Techniques. Ed. by Gianangelo Bracco and Bodil Holst.
Berlin, Heidelberg: Springer Berlin Heidelberg, 2013, pp. 565{597. isbn: 978-
3-642-34243-1. doi: 10 . 1007 / 978 - 3 - 642 - 34243 - 1 _ 19. url: https :
//doi.org/10.1007/978-3-642-34243-1_19.
[16] Dise~no y aplicaci´on de microscop´ıas avanzadas para el estudio de problemas
de mecanotransducci´on celular y nanoplasm´onica. https://digital.bl.
fcen.uba.ar/collection/tesis/document/tesis_n5716_Caldarola.
[17] R Dombrowski et al. \Tip-induced band bending by scanning tunneling spectroscopy of the states of the tip-induced quantum dot on InAs(110)". In: prb
59 (Mar. 1999), pp. 8043{. doi: 10.1103/PhysRevB.59.8043.
[18] C. Donnet et al. \Super-low friction of MoS2 coatings in various environments". In: Tribology International 29.2 (1996), pp. 123{128. issn: 0301-
679X. doi: https://doi.org/10.1016/0301- 679X(95)00094- K. url:
http://www.sciencedirect.com/science/article/pii/0301679X9500094K.
[19] B. Drevniok et al. \Methods and instrumentation for piezoelectric motors".
In: Review of Scientific Instruments 83.3 (2012), p. 033706. doi: 10.1063/
1.3694972. eprint: https://doi.org/10.1063/1.3694972. url: https:
//doi.org/10.1063/1.3694972.
[20] Ali Eftekhari. \Electrocatalysts for hydrogen evolution reaction". In: International Journal of Hydrogen Energy 42 (Mar. 2017). doi: 10.1016/j.
ijhydene.2017.02.125.
[21] Deyi Fu et al. \Molecular Beam Epitaxy of Highly-Crystalline Monolayer
Molybdenum Disulfide on Hexagonal Boron Nitride". In: Journal of the
American Chemical Society 139 (June 2017). doi: 10.1021/jacs.7b05131.
[22] Marco Furchi et al. \Mechanisms of Photoconductivity in Atomically Thin
MoS2". In: Nano Letters (Oct. 2014). doi: 10.1021/nl502339q.
[23] Xiumei Geng et al. \Pure and stable metallic phase molybdenum disulfide
nanosheets for hydrogen evolution reaction." In: Nature communications 7
(2016), p. 10672.
[24] L. Gmelin. Gmelin Handbook of inorganic and organometallic chemistry.
Gmelin Handbuch der anorganischen Chemie. Springer Verlag, 1995.
[25] Julia Gusakova et al. \Electronic Properties of Bulk and Monolayer TMDs:
Theoretical Study Within DFT Framework (GVJ-2e Method)". In: physica status solidi (a) 214 (Sept. 2017), p. 1700218. doi: 10 . 1002 / pssa .
201700218.
[26] Paul K. Hansma and Jerry Tersoff. \Scanning tunneling microscopy". In:
Journal of Applied Physics 61.2 (1987), R1{R24. doi: 10.1063/1.338189.
eprint: https://doi.org/10.1063/1.338189. url: https://doi.org/10.
1063/1.338189.
[27] Jinhua Hong et al. \Exploring atomic defects in molybdenum disulphide
monolayers". In: Nature communications 6 (Feb. 2015), p. 6293. doi: 10.
1038/ncomms7293.
[28] I. Horcas et al. \WSXM: A software for scanning probe microscopy and a
tool for nanotechnology". In: Review of Scientific Instruments 78.1 (2007),
p. 013705. doi: 10.1063/1.2432410. eprint: https://doi.org/10.1063/
1.2432410. url: https://doi.org/10.1063/1.2432410.
[29] Yuli Huang et al. \Bandgap tunability at single-layer molybdenum disulphide grain boundaries". In: Nature communications 6 (Feb. 2015), p. 6298.
doi: 10.1038/ncomms7298.
[30] David J. Hucknall. \3 - Vacuum pumps (high{ultra-high range)". In: Vacuum Technology and Applications. Ed. by David J. Hucknall. ButterworthHeinemann, 1991, pp. 79{125. isbn: 978-0-7506-1145-9. doi: https://doi.
org / 10 . 1016 / B978 - 0 - 7506 - 1145 - 9 . 50007 - 8. url: http : / / www .
sciencedirect.com/science/article/pii/B9780750611459500078.
[31] Ion Gauge. http://philiphofmann.net/ultrahighvacuum/ind_iongauge.
html.
[32] B. Jaffe, W.R. Cook, and H.L. Jaffe. Piezoelectric Ceramics, by Bernard
Jaffe and William R. Cook Jr. and Hans Jaffe. Non-metallic solids. Academic Press, 1971. url: https : / / books . google . com . tw / books ? id =
a1v7cQAACAAJ.
[33] Jordisite. https://www.mindat.org/min-2114.html.
[34] Min Kan et al. \Structures and Phase Transition of a MoS2 Monolayer". In:
The Journal of Physical Chemistry C 118 (Jan. 2014), pp. 1515{1522. doi:
10.1021/jp4076355.
[35] Min Kan et al. \Structures and Phase Transition of a MoS2 Monolayer". In:
The Journal of Physical Chemistry C 118 (Jan. 2014), pp. 1515{1522. doi:
10.1021/jp4076355.
[36] Santosh Kc et al. \Impact of intrinsic atomic defects on the electronic structure of MoS2 monolayers". In: Nanotechnology 25 (Aug. 2014), p. 375703.
doi: 10.1088/0957-4484/25/37/375703.
[37] Jungdae Kim et al. \Quantum size effects on the work function of metallic thin film nanostructures". In: Proceedings of the National Academy of
Sciences 107.29 (2010), pp. 12761{12765. issn: 0027-8424. doi: 10.1073/
pnas.0915171107. eprint: https://www.pnas.org/content/107/29/
12761.full.pdf. url: https://www.pnas.org/content/107/29/12761.
[38] Katsuyoshi Kobayashi and Jun Yamauchi. \Electronic structure and scanningtunneling-microscopy image of molybdenum dichalcogenide surfaces". In:
Phys. Rev. B 51 (23 June 1995), pp. 17085{17095. doi: 10.1103/PhysRevB.
51.17085. url: https://link.aps.org/doi/10.1103/PhysRevB.51.
17085.
[39] Antal Ko´os et al. \STM study of the MoS2 flakes grown on graphite: A model
system for atomically clean 2D heterostructure interfaces". In: Carbon 105
(Apr. 2016). doi: 10.1016/j.carbon.2016.04.069.
[40] A. Lasia. \Hydrogen evolution reaction". In: Handbook of Fuel Cells. American Cancer Society, 2010. isbn: 9780470974001. doi: 10.1002/9780470974001.
f204033. eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/
9780470974001.f204033. url: https://onlinelibrary.wiley.com/doi/
abs/10.1002/9780470974001.f204033.
[41] Andrzej Lasia. \Hydrogen evolution reaction". In: vol. 2. June 2003, pp. 414{
440. doi: 10.1002/9780470974001.f204033.
[42] Guoqing Li et al. \All The Catalytic Active Sites of MoS2 for Hydrogen
Evolution". In: Journal of the American Chemical Society 138 (Nov. 2016).
doi: 10.1021/jacs.6b05940.
[43] Xiao Li and Hongwei Zhu. \Two-dimensional MoS2: Properties, preparation, and applications". In: Journal of Materiomics 1.1 (2015), pp. 33{44.
issn: 2352-8478. doi: https://doi.org/10.1016/j.jmat.2015.03.
003. url: http : / / www . sciencedirect . com / science / article / pii /
S2352847815000040.
[44] Zhong Lin et al. \Defect engineering of two-dimensional transition metal
dichalcogenides". In: 2D Materials 3 (Apr. 2016), p. 022002. doi: 10.1088/
2053-1583/3/2/022002.
[45] Mengxi Liu et al. \Temperature-Triggered Sulfur Vacancy Evolution in Monolayer MoS 2 /Graphene Heterostructures". In: Small 13 (Aug. 2017), p. 1602967.
doi: 10.1002/smll.201602967.
[46] Xiaolong Liu et al. \Point Defects and Grain Boundaries in Rotationally
Commensurate MoS2 on Epitaxial Graphene". In: The Journal of Physical
Chemistry C 120 (Mar. 2016), pp. 20798{20805. doi: 10.1021/acs.jpcc.
6b02073.
[47] Xiaolong Liu et al. \Rotationally Commensurate Growth of MoS2 on Epitaxial Graphene". In: ACS Nano 10 (Nov. 2015), pp. 1067{1075. doi: 10.
1021/acsnano.5b06398.
[48] Chih-Pin Lu et al. \MoS2: Choice Substrate for Accessing and Tuning the
Electronic Properties of Graphene". In: Physical Review Letters 113 (Sept.
2014). doi: 10.1103/PhysRevLett.113.156804.
[49] Arend M van der Zande et al. \Grains and grain boundaries in highly crystalline monolayer molybdenum disulfide". In: Nature materials 12 (May
2013). doi: 10.1038/nmat3633.
[50] John William Draper M.D. \LIV. On the production of light by heat". In:
The London, Edinburgh, and Dublin Philosophical Magazine and Journal of
Science 30.202 (1847), pp. 345{360. doi: 10 . 1080 / 14786444708647190.
eprint: https://doi.org/10.1080/14786444708647190. url: https:
//doi.org/10.1080/14786444708647190.
[51] Kin Fai Mak et al. \Atomically Thin MoS2: A New Direct-Gap Semiconductor". In: Phys. Rev. Lett. 105 (13 Sept. 2010), p. 136805. doi: 10.1103/
PhysRevLett.105.136805. url: https://link.aps.org/doi/10.1103/
PhysRevLett.105.136805.
[52] Michael Man et al. \Protecting the properties of monolayer MoS2 on silicon
based substrates with an atomically thin buffer". In: Scientific Reports 6
(Feb. 2016), p. 20890. doi: 10.1038/srep20890.
[53] P. K. Mohapatra et al. \Strictly monolayer large continuous MoS2 films on
diverse substrates and their luminescence properties". In: Applied Physics
Letters 108.4 (2016), p. 042101. doi: 10.1063/1.4940751. eprint: https:
//doi.org/10.1063/1.4940751. url: https://doi.org/10.1063/1.
4940751.
[54] Molybdenum disulfide. https://en.wikipedia.org/wiki/Molybdenum_
disulfide.
[55] Azhagurajan Mukkannan et al. \In Situ Visualization of Lithium Ion Intercalation into MoS2 Single Crystals using Differential Optical Microscopy
with Atomic Layer Resolution". In: Journal of the American Chemical Society 138 (Feb. 2016). doi: 10.1021/jacs.5b11849.
[56] Oerlikon Leybold Vacuum. https://www3.nd.edu/~nsl/Lectures/urls/
LEYBOLD_FUNDAMENTALS.pdf.
[57] Oil Sealed Rotary Vane Pumps. https : / / vacaero . com / information -
resources/vacuum-pump-technology-education-and-training/195875-
oil-sealed-rotary-vane-pumps.html.
[58] J. R. Oppenheimer. \Three Notes on the Quantum Theory of Aperiodic
Effects". In: Phys. Rev. 31 (1 Jan. 1928), pp. 66{81. doi: 10.1103/PhysRev.
31.66. url: https://link.aps.org/doi/10.1103/PhysRev.31.66.
[59] Yixin Ouyang et al. \Activating Inert Basal Planes of MoS2 for Hydrogen
Evolution Reaction through the Formation of Different Intrinsic Defects".
In: Chemistry of Materials 28.12 (2016), pp. 4390{4396. doi: 10.1021/acs.
chemmater.6b01395. eprint: https://doi.org/10.1021/acs.chemmater.
6b01395. url: https://doi.org/10.1021/acs.chemmater.6b01395.
[60] S. H. Pan, E. W. Hudson, and J. C. Davis. \3He refrigerator based very
low temperature scanning tunneling microscope". In: Review of Scientific
Instruments 70.2 (1999), pp. 1459{1463. doi: 10.1063/1.1149605. eprint:
https://doi.org/10.1063/1.1149605. url: https://doi.org/10.1063/
1.1149605.
[61] Pfeiffer Compact Turbo HiPaceTM. https://www.lesker.com/newweb/
vacuum_pumps/turbopump_pfeiffer_hipace.cfm.
[62] M. Planck and M. Masius. The Theory of Heat Radiation. Blakiston, 1914.
url: http://books.google.co.uk/books?id=2PR%5C_AAAAMAAJ.
[63] Jorge Quereda et al. \Strain engineering of Schottky barriers in single- and
few-layer MoS2 vertical devices". In: 2D Materials 4 (Jan. 2017). doi: 10.
1088/2053-1583/aa5920.
[64] B Radisavljevic et al. \Single-layer MoS2 transistors". In: Nature nanotechnology 6 (Jan. 2011), pp. 147{50. doi: 10.1038/nnano.2010.279.
[65] Philipp Rahe, R Bechstein, and A K¨uhnle. \Vertical and lateral drift corrections of scanning probe microscopy images". In: Journal of Vacuum Science & Technology B - J VAC SCI TECHNOL B 28 (May 2010). doi:
10.1116/1.3360909.
[66] Residual Gas Analyzer. http://https://www.iitk.ac.in/ibc/RGA.pdf.
[67] Benjamin Robinson et al. \Structural, optical and electrostatic properties of
single and few-layers MoS2: effect of substrate". In: 2D Materials 2 (Mar.
2015), p. 015005. doi: 10.1088/2053-1583/2/1/015005.
[68] Junga Ryou et al. \Monolayer MoS2 Bandgap Modulation by Dielectric Environments and Tunable Bandgap Transistors". In: Scientific reports 6 (July
2016), p. 29184. issn: 2045-2322. doi: 10.1038/srep29184. url: http:
//europepmc.org/articles/PMC4932597.
[69] Parikshit Sahatiya, S Solomon Jones, and Sushmee Badhulika. \Direct, large
area growth of few-layered MoS2 nanostructures on various flexible substrates: growth kinetics and its effect on photodetection studies". In: Flexible and Printed Electronics 3.1 (Jan. 2018), p. 015002. doi: 10.1088/2058-
8585/aaa4a5. url: https://doi.org/10.1088%2F2058-8585%2Faaa4a5.
[70] Scanning Tunneling Microscopy. https://www.nanoscience.com/techniques/
scanning-tunneling-microscopy/.
[71] L. Schulz. \Sputter ion pumps". In: (1999).
[72] Roger F. Sebenik et al. \Molybdenum and Molybdenum Compounds". In:
Ullmann’s Encyclopedia of Industrial Chemistry. American Cancer Society,
2000. isbn: 9783527306732. doi: 10 . 1002 / 14356007 . a16 _ 655. eprint:
https : / / onlinelibrary . wiley . com / doi / pdf / 10 . 1002 / 14356007 .
a16_655. url: https://onlinelibrary.wiley.com/doi/abs/10.1002/
14356007.a16_655.
[73] Tatsuya Shinagawa, Angel Garcia-Esparza, and Kazuhiro Takanabe. \Insight on Tafel slopes from a microkinetic analysis of aqueous electrocatalysis
for energy conversion". In: Scientific reports 5 (Sept. 2015), p. 13801. doi:
10.1038/srep13801.
[74] Sebastian Stepanow, Nian Lin, and Johannes V Barth. \Modular assembly of
low-dimensional coordination architectures on metal surfaces". In: Journal of
Physics Condensed Matter 20 (May 2008), p. 184002. doi: 10.1088/0953-
8984/20/18/184002.
[75] Sherman Tan et al. \Chemical Stabilization of 1T’ phase Transition Metal
Dichalcogenides". In: Journal of the American Chemical Society 139 (Jan.
2017). doi: 10.1021/jacs.6b13238.
[76] Sherman Tan et al. \Temperature and Phase-Dependent Phonon Renormalization in 1T’-MoS2". In: ACS Nano 12 (Apr. 2018). doi: 10.1021/
acsnano.8b02649.
[77] J. Tersoff and D. R. Hamann. \Theory of the scanning tunneling microscope". In: Phys. Rev. B 31 (2 Jan. 1985), pp. 805{813. doi: 10.1103/
PhysRevB.31.805. url: https://link.aps.org/doi/10.1103/PhysRevB.
31.805.
[78] Charlie Tsai et al. \Electrochemical generation of sulfur vacancies in the
basal plane of MoS2 for hydrogen evolution". In: Nature communications 8
(Apr. 2017), p. 15113. issn: 2041-1723. doi: 10.1038/ncomms15113. url:
http://europepmc.org/articles/PMC5530599.
[79] Meng-Lin Tsai et al. \Monolayer MoS2 Heterojunction Solar Cells". In:
ACS Nano 8.8 (2014). PMID: 25046764, pp. 8317{8322. doi: 10 . 1021 /
nn502776h. eprint: https://doi.org/10.1021/nn502776h. url: https:
//doi.org/10.1021/nn502776h.
[80] A Vazquez Carazo. \Novel piezoelectric transducers for high voltage measurements". In: (July 2002).
[81] Damien Voiry, Aditya Mohite, and Manish Chhowalla. \Phase engineering of
transition metal dichalcogenides". In: Chem. Soc. Rev. 44 (9 2015), pp. 2702{
2712. doi: 10.1039/C5CS00151J. url: http://dx.doi.org/10.1039/
C5CS00151J.
[82] Jiayu Wan et al. \Tuning two-dimensional nanomaterials by intercalation:
Materials, properties and applications". In: Chemical Society Reviews 45
(Oct. 2016). doi: 10.1039/c5cs00758e.
[83] Shanshan Wang et al. \Shape Evolution of Monolayer MoS2 Crystals Grown
by Chemical Vapor Deposition". In: Chemistry of Materials 26 (Oct. 2014).
doi: 10.1021/cm5025662.
[84] Matthew Webb et al. \A simple method to produce almost perfect graphene
on highly oriented pyrolytic graphite". In: Carbon 49 (Mar. 2011), pp. 3242{
3249. doi: 10.1016/j.carbon.2011.03.050.
[85] What is the difference between Rotary Vane and Diaphragm vacuum pumps?
https : / / camblab . info / wp / index . php / what - is - the - difference -
between-rotary-vane-and-diaphragm-vacuum-pumps/.
[86] Ke Wu et al. \Controllable defects implantation in MoS2 grown by chemical
vapor deposition for photoluminescence enhancement". In: Nano Research
11.8 (Aug. 2018), pp. 4123{4132. issn: 1998-0000. doi: 10.1007/s12274-
018-1999-7. url: https://doi.org/10.1007/s12274-018-1999-7.
[87] Fernando Wypych. \1T-MoS2, A New Metallic Modification of Molybdenum
Disulfide". In: Journal of The Chemical Society, Chemical Communications
19 (Oct. 1992). doi: 10.1039/c39920001386.
[88] Yong Xie et al. \Controllable growth of monolayer MoS2 by chemical vapor
deposition via close MoO2 precursor for electrical and optical applications".
In: Nanotechnology 28 (Dec. 2016). doi: 10.1088/1361-6528/aa5439.
[89] Hai Xu et al. \Observation of Gap Opening in 1T’ Phase MoS2 Nanocrystals". In: Nano Letters 18 (July 2018). doi: 10 . 1021 / acs . nanolett .
8b01953.
[90] Eilam Yalon et al. \Energy Dissipation in Monolayer MoS2 Electronics". In:
Nano letters 17 (Apr. 2017). doi: 10.1021/acs.nanolett.7b00252.
[91] Pengfei Yan et al. \Chemical vapor deposition of monolayer MoS2 on sapphire, Si and GaN substrates". In: Superlattices and Microstructures 120
(May 2018). doi: 10.1016/j.spmi.2018.05.049.
[92] Gonglan Ye et al. \Defects Engineered Monolayer MoS2 for Improved Hydrogen Evolution Reaction". In: Nano letters 16 (Jan. 2016). doi: 10.1021/
acs.nanolett.5b04331.
[93] Youngki Yoon, Kartik Ganapathi, and Sayeef Salahuddin. \How Good Can
Monolayer MoS2 Transistors Be?" In: Nano Letters 11.9 (2011). PMID:
21790188, pp. 3768{3773. doi: 10.1021/nl2018178. eprint: https://doi.
org/10.1021/nl2018178. url: https://doi.org/10.1021/nl2018178.
[94] Chendong Zhang et al. \Direct Imaging of Band Profile in Single Layer MoS2
on Graphite: Quasiparticle Energy Gap, Metallic Edge States, and Edge
Band Bending". In: Nano letters 14 (May 2014). doi: 10.1021/nl501133c.
[95] Wensi Zhang et al. \Synthesis and sensor applications of MoS2-based nanocomposites". In: Nanoscale 7 (44 2015), pp. 18364{18378. doi: 10.1039/C5NR06121K.
url: http://dx.doi.org/10.1039/C5NR06121K.
[96] G´abor Zsolt Magda et al. \Exfoliation of large-area transition metal chalcogenide single layers". In: Scientific Reports 5 (Oct. 2015), p. 14714. doi:
10.1038/srep14714.