Skip to Main Content
 

Global Search Box

 
 
 
 

ETD Abstract Container

Abstract Header

Synthesis and Characterization of Large Area Few-layer MoS2 and WS2 Films

Abstract Details

2014, Master of Science, Ohio State University, Chemistry.
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.
Yiying Wu, Dr. (Advisor)
Joshua Goldberger, Dr. (Committee Member)
106 p.

Recommended Citations

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)