Now showing items 1-20 of 31

    • Investigation of interfacial oxidation control using sacrificial metallic Al and La passivation layers on InGaAs 

      Brennan, Barry; Milojevic, Marko; Contreras-Guerrero, Roccio; Kim, Hyun-Chul; Lopez-Lopez, Maximo; Kim, Jiyoung; Wallace, Robert M. (2012-05-25)
      The ability of metallic Al and La interlayers to control the oxidation of InGaAs substrates is examined by monochromatic x-ray photoelectron spectroscopy (XPS) and compared to the interfacial chemistry of atomic layer ...
    • In situ atomic layer deposition half cycle study of Al2O 3 growth on AlGaN 

      Brennan, Barry; Qin, Xiaoye; Dong, Hong; Kim, Jiyoung; Wallace, Robert M. (American Institute of Physics, 2012-11-10)
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    • In Situ Study of the Role of Substrate Temperature during Atomic Layer Deposition of HfO2 on InP 

      Dong, Hong; Santosh, KC; Qin, Xiaoye; Brennan, Barry; McDonnell, Steven; Zhernokletov, Dmitry; Hinkle, Christopher L.; Kim, Jiyoung; Cho, Kyeongjie; Wallace, Robert M. (2013-10-16)
      The dependence of the "self cleaning" effect of the substrate oxides on substrate temperature during atomic layer deposition (ALD) of HfO₂ on various chemically treated and native oxide InP (100) substrates is investigated ...
    • Selectivity of Metal Oxide Atomic Layer Deposition on Hydrogen Terminated and Oxidized Si(001)-(2x1) Surface 

      Longo, Roberto C.; McDonnell, Stephen; Dick, D.; Wallace, Robert M.; Chabal, Yves J.; Owen, James H. G.; Ballard, Josh B.; Randall, John N.; Cho, Kyeongjae (A V S Amer Inst Physics, 2014-02-10)
      In this work, the authors used density-functional theory methods and x-ray photoelectron spectroscopy to study the chemical composition and growth rate of HfO₂, Al₂O₃, and TiO₂ thin films grown by in-situ atomic layer ...
    • Accumulation Capacitance Frequency Dispersion of Ⅲ-Ⅴ Metal-Insulator-Semiconductor Devices due to Disorder Induced Gap States 

      Galatage, R. V.; Zhernokletov, Dmitry M.; Dong, Hong; Brennan, Barry; Hinkle, Christopher L.; Wallace, Robert M.; Vogel, E. M. (American Institute of Physics Inc., 2014-07-07)
      The origin of the anomalous frequency dispersion in accumulation capacitance of metal-insulator-semiconductor devices on InGaAs and InP substrates is investigated using modeling, electrical characterization, and chemical ...
    • 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, ...
    • A Kinetic Monte Carlo Simulation Method of Van Der Waals Epitaxy for Atomistic Nucleation-Growth Processes of Transition Metal Dichalcogenides 

      Nie, Yifan; Liang, Chaoping; Cha, Pil-Ryung; Colombo, Luigi; Wallace, Robert M.; Cho, Kyeongjae (Nature Publishing Group, 2018-08-31)
      Controlled growth of crystalline solids is critical for device applications, and atomistic modeling methods have been developed for bulk crystalline solids. Kinetic Monte Carlo (KMC) simulation method provides detailed ...
    • A Crystalline Oxide Passivation on In₀․₅₃Ga₀․₄₇As (100) 

      Qin, Xiaoye; Wang, W. -E; Droopad, R.; Rodder, M. S.; Wallace, Robert M. (American Institute of Physics Inc, 2018-09-24)
      The passivation of In₀․₅₃Ga₀․₄₇As surfaces is highly desired for transistor performance. In this study, the feasibility of a crystalline oxide passivation on In₀․₅₃Ga₀․₄₇As (100) is demonstrated experimentally. The (3 × ...
    • UV-Ozone Functionalization of 2D Materials 

      McDonnell, Stephen J.; Wallace, Robert M. (Springer, 2018-10-04)
      Integrating two-dimensional (2D) materials into the current nanoelectronic process requires control over the deposition of gate oxides onto these materials. Atomic layer deposition (ALD) relies on surface dangling bonds ...
    • 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 ...
    • 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, ...
    • 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 ...
    • 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. ...
    • In Situ Study of E-Beam Al And Hf Metal Deposition on Native Oxide InP (100) 

      Dong, Hong; Santosh, KC; Azcatl, Angelica; Cabrera, Wilfredo; Qin, Xiaoye; Brennan, Barry; Zhernokletov, Dmitry; Cho, Kyeongjie; Wallace, Robert M.
      The interfacial chemistry of thin Al (∼3 nm) and Hf (∼2 nm) metal films deposited by electron beam (e-beam) evaporation on native oxide InP (100) samples at room temperature and after annealing has been studied by in situ ...
    • 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 ...
    • A Crystalline Oxide Passivation for Al₂O₃/AlGaN/GaN 

      Qin, Xiaoye; Dong, Hong; Kim, Jiyoung; Wallace, Robert M.
      In situ X-ray photoelectron spectroscopy and low energy electron diffraction are performed to study the formation of a crystalline oxide on the AlGaN surface. The oxidation of the AlGaN surface is prepared by annealing and ...
    • Trimethyl-Aluminum and Ozone Interactions with Graphite in Atomic Layer Deposition of Al2O3 

      McDonnell, Stephen; Pirkle, Adam R.; Kim, Jiyoung; Colombo, Luigi; Wallace, Robert M.
      A study of the chemical interactions between the atomic layer deposition (ALD) Al2O3 precursors trimethlyaluminum (TMA) and ozone (TMA/O-3) and sp(2) carbon surfaces is presented. In-situ x-ray photoelectron spectroscopy ...
    • Investigation of Arsenic and Antimony Capping Layers, and Half Cycle Reactions During Atomic Layer Deposition of Al₂O₃ on GaSb(100) 

      Zhernokletov, Dmitry M.; Dong, Hong; Brennan, Barry; Kim, Jiyoung; Wallace, Robert M.; Yakimov, M.; Tokranov, V.; Oktyabrsky, S.
      In-situ monochromatic x-ray photoelectron spectroscopy, low energy electron diffraction, ion scattering spectroscopy, and transmission electron microscopy are used to examine the GaSb(100) surfaces grown by molecular beam ...
    • 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 ...