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Rui Yang_2016 PhD Thesis_Final.pdf (17.72 MB)

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Coupling Two-Dimensional (2D) Nanoelectromechanical Systems (NEMS) with Electronic and Optical Properties of Atomic Layer Molybdenum Disulfide (MoS2)

Yang, Rui
http://rave.ohiolink.edu/etdc/view?acc_num=case1459776436

Abstract Details

2016, Doctor of Philosophy, Case Western Reserve University, EECS - Electrical Engineering.
The discovery of two-dimensional (2D) materials has attracted tremendous interest and led to a great deal of investment due to their unique properties that are not present in three-dimensional (3D) or one-dimensional (1D) materials. Though graphene as the flagship 2D material has been extensively studied, it is a semimetal without a natural bandgap, and the difficulties in creating a useful bandgap has limited its applications in logic circuits, photonic devices and tunable devices. 2D semiconductors such as molybdenum disulfide (MoS2) compensate for graphene because they have a natural sizable bandgap, and thus can largely extend the applications of 2D materials. In order to fully exploit the distinct properties of these 2D semiconductors toward advantageous performance as applicable devices, it would be ideal to synthetically consider the electronic, mechanical, and optical properties of these materials. While MoS2 field-effect transistors (FETs), nanoelectromechanical systems (NEMS), and optoelectronic devices have been demonstrated, there are still numerous problems that need to be solved before applying the devices for sensing, computing, and communication applications that require high performance (sensitivity, reliability, responsivity, etc.). In this dissertation, state-of-the-art studies of MoS2 electronics are first introduced and surveyed. The electrical breakdown limit of MoS2 FETs is investigated because it determines the current carrying capability and failure modes, which are critical for integrated circuit applications. A completely-dry transfer method combined with vacuum thermal annealing is developed to fully harness the intrinsic properties of MoS2 without inducing residue on the surface. Then the mechanical properties and devices of MoS2 are presented. The first MoS2 nanomechanical resonator on a flexible PDMS substrate that is tolerant to a large amount of bending and straining is demonstrated, showing promise for flexible and foldable electronics. The temperature dependence of MoS2 resonators is also studied. Finally, the coupling of electrical and mechanical properties of MoS2 are explored using the first all-electrical readout of 1-, 2-, 3-layer MoS2 NEMS resonators, with the thickness confirmed with both Raman and photoluminescence (PL) characterization. The devices take the form of vibrating-channel transistors, with multimode resonances highly tunable by the gate voltage, which holds promises and intriguing potential for real-time sensing and signal processing applications.
Philip Feng (Advisor)
Christian Zorman (Committee Member)
Hongping Zhao (Committee Member)
Xuan Gao (Committee Member)
Soumyajit Mandal (Committee Member)
209 p.
Electrical Engineering; Nanotechnology
2D Semiconductor; MoS2; 2D NEMS Resonator; 2D Field-Effect Transistor; Electrical Readout; Optical Interferometry; Dry Transfer; Electromechanical Coupling

Recommended Citations

Citations

  • Yang, R. (2016). Coupling Two-Dimensional (2D) Nanoelectromechanical Systems (NEMS) with Electronic and Optical Properties of Atomic Layer Molybdenum Disulfide (MoS2) [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1459776436

    APA Style (7th edition)

  • Yang, Rui. Coupling Two-Dimensional (2D) Nanoelectromechanical Systems (NEMS) with Electronic and Optical Properties of Atomic Layer Molybdenum Disulfide (MoS2). 2016. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1459776436.

    MLA Style (8th edition)

  • Yang, Rui. "Coupling Two-Dimensional (2D) Nanoelectromechanical Systems (NEMS) with Electronic and Optical Properties of Atomic Layer Molybdenum Disulfide (MoS2)." Doctoral dissertation, Case Western Reserve University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1459776436

    Chicago Manual of Style (17th edition)

case1459776436
207
© 2016, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.