报告人：Zhixian Zhou 副教授
Department of Physics and Astronomy
Wayne State University
Detroit, MI 48201
题目: Contact and Interface Engineering in Field-Effect Transistors of Two-Dimensional Layered Semiconductors beyond Graphene
地点：909号楼一楼B会议室(Conference Room B, 909-1F)
The successful isolation of two-dimensional (2D) graphene has stimulated research on a broad range of other 2D materials, among which layered transition metal dichalcogenides (TMDs) have attracted particular attention. The semiconducting members of the TMD family including MoS2, MoSe2, WS2 and WSe2 have not only demonstrated many of the "graphene like" properties highly desirable for electronic applications such as a relatively high mobility, mechanical flexibility, chemical and thermal stability, and the absence of dangling bonds, but also have a substantial band gap (1 ~ 2 eV depending on the material and its thickness), which is absent in 2D graphene but required for mainstream logic applications. However, the electrical transport mechanisms in TMD FETs, particularly, the factors that limit the ultimate device mobility are poorly understood. Moreover, while low resistance Ohmic contacts are essential for optimizing the FET performance, large bandgap semiconductors often fail to form Ohmic contacts with metals. In order to optimize the performance of TMD field effect transistors (FETs), it is crucial to use low resistance Ohmic contacts.1 In this talk, I will discuss our recent work on the application of graphene as a work-function-tunable electrode material for atomically thin layered TMDs, and to systematically study the electric-field tunability of the graphene/TMD contacts, as well as the intrinsic charge transport properties of the TMD channel in the limit of low resistance Ohmic contacts. In addition to contact engineering, I will also discuss the important role of the substrate/dielectric in carrier mobility.2
1. Perera, M. M.; Lin, M.-W.; Chuang, H.-J.; Chamlagain, B. P.; Wang, C.; Tan, X.; Cheng, M. M.-C.; Tománek, D.; Zhou, Z. Improved Carrier Mobility in Few-Layer Mos2 Field-Effect Transistors with Ionic-Liquid Gating. ACS Nano 2013, 7, 4449-4458.
2. Chamlagain, B.; Li, Q.; Ghimire, N. J.; Chuang, H.-J.; Perera, M. M.; Tu, H.; Xu, Y.; Pan, M.; Xiao, D.; Yan, J.; Mandrus, D.; Zhou, Z. Mobility Improvement and Temperature Dependence in Mose2 Field-Effect Transistors on Parylene-C Substrate. ACS Nano 2014, 10.1021/nn501150r.
Lanzhou University, Lanzhou, Gansu Physics BS
Florida State University, Tallahassee, FL Physics Ph.D.
Wayne State University, Detroit, MI Associate Professor 2013 – present
Wayne State University, Detroit, MI Assistant Professor 2007 – 2013
Oak Ridge National Laboratory, Oak Ridge, TN Research Associate 2005 – 2007
National High Magnetic Field Lab, Tallahassee, FL Graduate Research Assistant 1999 – 2004
Research Interests and Activities:
Fabrication, characterization, and electrical transport studies of various nanoscale materials and devices including graphene, layered transition-metal-dichalcogenides, back phosphorus, and their heterostructures.
Current Research Funding:
NSF-ECCS and NSF-DMR