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Lu Ma Master thesis-1227.pdf (3.75 MB)
ETD Abstract Container
Abstract Header
Synthesis and Characterization of Large Area Few-layer MoS2 and WS2 Films
Author Info
Ma, Lu
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=osu1388149255
Abstract Details
Year and Degree
2014, Master of Science, Ohio State University, Chemistry.
Abstract
Transition metal dichalcogenides (TMDs) bonded by a weak Van der Waals force between layers can be exfoliated to a single layer or a few layers. These ultrathin materials (less than 10 atoms thick) belong to the family of two-dimensional (2D) materials. As dimensionality reduced, 2D materials have unique heat and charge transport properties. With sizable band gaps, 2D TMDs arouse both fundamental and practical interest. However, the synthesis of orientated single- or few- layer TMDs with large area remains challenging. Here, a facile chemical vapor-metal conversion method was employed to get (0001)-orientated MoS2 and WS2 few-layer films with large area. In addition, by inserting another metal layer into the precursor Mo layers, doped MoS2 films (e.g. Nb doped MoS2 films) were successfully synthesized by one-step chemical vapor-metal conversion process. The thickness of the film was controlled by tuning the thickness of the starting metal layers. Doping density varied with the thickness of the doping metal layers. The atomic force microscopy (AFM), high resolution x-ray diffractometer (HRXRD), Raman spectroscopy and transmission electron microscopy (TEM) were used to characterize the layered TMD films. Transport properties were measured by the Hall Measurements, the Transmission Linear Measurement (TLM) and the Field-effect Transistor (FET) measurements. The pure few-layer MoS2 films were n-type and had a low background carrier concentration of ~1016 cm-3 with a high electron mobility of up to 12 cm2V-1 s-1. The Nb-doped MoS2 films were p-type and showed highly degenerate doped behavior. By decreasing the doping density, the hole mobility of Nb-doped MoS2 films increased from 0.5 cm2V-1 s-1to 8.5 cm2V-1 s-1. Moreover, MoS2/WS2 planar heterojunctions were made by the same chemical vapor-metal conversion method with one-step heating.
Committee
Yiying Wu, Dr. (Advisor)
Joshua Goldberger, Dr. (Committee Member)
Pages
106 p.
Subject Headings
Chemistry
Keywords
2D material, few-layer MoS2 film, mobility, p-MoS2
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Citations
Ma, L. (2014).
Synthesis and Characterization of Large Area Few-layer MoS2 and WS2 Films
[Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1388149255
APA Style (7th edition)
Ma, Lu.
Synthesis and Characterization of Large Area Few-layer MoS2 and WS2 Films.
2014. Ohio State University, Master's thesis.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=osu1388149255.
MLA Style (8th edition)
Ma, Lu. "Synthesis and Characterization of Large Area Few-layer MoS2 and WS2 Films." Master's thesis, Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1388149255
Chicago Manual of Style (17th edition)
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Document number:
osu1388149255
Download Count:
4,563
Copyright Info
© 2013, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.