Now showing items 1-9 of 9

    • Atomically Thin Resonant Tunnel Diodes Built from Synthetic van der Waals Heterostructures 

      Lin, Yu-Chuan; Ghosh, Ram Krishna; Addou, Rafik; Lu, Ning; Eichfeld, Sarah M.; Zhu, Hui; Li, Ming-Yang; Peng, Xin; Kim, Moon J.; Li, Lain-Jong; Wallace, Robert M.; Datta, Suman; Robinson, Joshua A.
      Vertical integration of two-dimensional van der Waals materials is predicted to lead to novel electronic and optical properties not found in the constituent layers. Here, we present the direct synthesis of two unique, ...
    • Covalent Nitrogen Doping in Molecular Beam Epitaxy-Grown and Bulk WSe₂ 

      Khosravi, Ava; Addou, Rafik; Smyth, Christopher M.; Yue, Ruoyu; Cormier, Christopher R.; Kim, Jiyoung; Hinkle, Christopher L.; Wallace, Robert M. (American Institute of Physics Inc, 2018-10-22)
      Covalent p-type doping of WSe₂ thin films grown by molecular beam epitaxy and WSe₂ exfoliated from bulk crystals is achieved via remote nitrogen plasma exposure. X-ray photoelectron and Raman spectroscopies indicate ...
    • Engineering The Palladium-WSe₂ Interface Chemistry for Field Effect Transistors with High-Performance Hole Contacts 

      Smyth, Christopher M.; Walsh, Lee A.; Bolshakov, Pavel; Catalano, Massimo; Addou, Rafik; Wang, Luhua; Kim, Jiyoung; Kim, Moon J.; Young, Chadwin D.; Hinkle, Christopher L.; Wallace, Robert M. (Amer Chemical Soc, 2018-12-07)
      Palladium has been widely employed as a hole contact to WSe₂ and has enabled, at times, the highest WSe₂ transistor performance. However, there are orders of magnitude variation across the literature in Pd-WSe₂ contact ...
    • Enhancing Interconnect Reliability and Performance by Converting Tantalum to 2D Layered Tantalum Sulfide at Low Temperature 

      Lo, C. -L; Catalano, Massimo; Khosravi, Ava; Ge, W.; Ji, Y.; Zemlyanov, D. Y.; Wang, Luhua; Addou, Rafik; Liu, Y.; Wallace, Robert M.; Kim, Moon J.; Chen, Z. (Wiley-VCH Verlag, 2019-06-11)
      The interconnect half-pitch size will reach ≈20 nm in the coming sub-5 nm technology node. Meanwhile, the TaN/Ta (barrier/liner) bilayer stack has to be >4 nm to ensure acceptable liner and diffusion barrier properties. ...
    • High-κ Dielectric on ReS₂: In-Situ Thermal Versus Plasma-Enhanced Atomic Layer Deposition of Al₂O₃ 

      Khosravi, Ava; Addou, Rafik; Catalano, Massimo; Kim, Jiyoung; Wallace, Robert M. (MDPI AG, 2019-03-30)
      We report an excellent growth behavior of a high-κ dielectric on ReS₂ , a two-dimensional (2D) transition metal dichalcogenide (TMD). The atomic layer deposition (ALD) of an Al₂O₃ thin film on the UV-Ozone pretreated surface ...
    • MoS₂ Functionalization for Ultra-Thin Atomic Layer Deposited Dielectrics 

      Azcatl, Angelica; McDonnell, Stephen; KC, Santosh; Peng, Xin; Dong, Hong; Qin, Xiaoye; Addou, Rafik; Mordi, Greg I.; Lu, Ning; Kim, Jiyoung; Kim, Moon J.; Cho, Kyeongjae; Wallace, Robert M.
      The effect of room temperature ultraviolet-ozone (UV-O₃) exposure of MoS₂ on the uniformity of subsequent atomic layer deposition of Al₂O₃ is investigated. It is found that a UV-O₃ pre-treatment removes adsorbed carbon ...
    • Nucleation and Growth of WSe₂: Enabling Large Grain Transition Metal Dichalcogenides 

      Yue, Ruoyu; Nie, Yifan; Walsh, Lee A.; Addou, Rafik; Liang, Chaoping; Lu, Ning; Barton, Adam T.; Zhu, Hui; Che, Zifan; Barrera, Diego; Cheng, Lanxia; Cha, Pil-Ryung; Chabal, Yves J.; Hsu, Julia W. P.; Kim, Jiyoung; Kim, Moon J.; Colombo, Luigi; Wallace, Robert M.; Cho, Kyeongjae; Hinkle, Christopher L. (IOP Publishing Ltd, 2017-09-22)
      The limited grain size (< 200 nm) for transition metal dichalcogenides (TMDs) grown by molecular beam epitaxy (MBE) reported in the literature thus far is unsuitable for high-performance device applications. In this work, ...
    • Tuning Electronic Transport in Epitaxial Graphene-Based Van Der Waals Heterostructures 

      Lin, Yu-Chuan; Li, Jun; de la Barrera, Sergio,C.; Eichfeld, Sarah M.; Nie, Yifan; Addou, Rafik; Mende, Patrick C.; Wallace, Robert M.; Cho, Kyeongjae; Feenstra, Randall M.; Robinson, Joshua A.
      Two-dimensional tungsten diselenide (WSe₂) has been used as a component in atomically thin photovoltaic devices, field effect transistors, and tunneling diodes in tandem with graphene. In some applications it is necessary ...
    • Using Photoelectron Spectroscopy in the Integration of 2D Materials for Advanced Devices 

      Addou, Rafik; Wallace, Robert M. (Elsevier Science B.V., 2019-01-31)
      The first commercial applications of two dimensional (2D) layered materials such as graphite and MoS₂ used their lubricant properties. Following the discovery of graphene and its potential applications in various fields, ...