Browsing Cho, Kyeongjae by Issue Date
Now showing items 1-20 of 27
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In Situ Study of the Role of Substrate Temperature during Atomic Layer Deposition of HfO2 on InP
(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
(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 ... -
Tunable H₂ Binding on Alkaline and Alkaline Earth Metals Decorated Graphene Substrates from First-Principles Calculations
(Pergamon-Elsevier Science Ltd, 2017-04-13)Based on first-principles calculations, the H-2 adsorptions onto six types of modified graphene substrates decorated with light metals (Li, Na, K, Be, Mg, Ca) are investigated to shed light on the factors affecting the H-2 ... -
Nucleation and Growth of WSe₂: Enabling Large Grain Transition Metal Dichalcogenides
(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, ... -
Investigation of the Hydrothermal Aging of an Mn-Based Mullite SmMn₂O₅ Catalyst of NO Oxidation
(Royal Society of Chemistry, 2017-10-20)Hydrothermal aging tests are important to carry out when evaluating the hydrothermal durability of heterogeneous catalysts in vehicle exhaust emission. Here, we explored the effect of aging on an efficient Mn-based mullite ... -
A Kinetic Monte Carlo Simulation Method of Van Der Waals Epitaxy for Atomistic Nucleation-Growth Processes of Transition Metal Dichalcogenides
(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 ... -
WSe₂ Homojunctions and Quantum Dots Created by Patterned Hydrogenation of Epitaxial Graphene Substrates
(IOP Publishing Ltd, 2019-01-17)Scanning tunneling microscopy (STM) at 5 K is used to study WSe₂ layers grown on epitaxial graphene which is formed on Si-terminated SiC(0 0 0 1). Specifically, a partial hydrogenation process is applied to intercalate ... -
Tuning the Structure of Bifunctional Pt/SmMn₂O₅ Interfaces for Promoted Low-Temperature CO Oxidation Activity
(Royal Society of Chemistry, 2019-01-30)The interfacial structure of metal-oxide composite catalysts plays a vital role in heterogeneous catalysis, which is crucial to the adsorption and activation of reactants. Herein, the interfacial effects of bare and Fe/Co/Ni ... -
Ab-Initio Design of Novel Cathode Material LiFeP₁₋ₓSiₓO₄ for Rechargeable Li-Ion Batteries
(Elsevier Ltd, 2019-04-27)In this study, newly designed cathode material LiFeP₁₋ₓSiₓO₄, with silicon mixed in LiFePO₄ is investigated using the density functional theory. Its most optimized structure is the olivine structure of the Pnma space ... -
ZnO Composite Nanolayer with Mobility Edge Quantization for Multi-Value Logic Transistors
(Nature Publishing Group, 2019-04-30)A quantum confined transport based on a zinc oxide composite nanolayer that has conducting states with mobility edge quantization is proposed and was applied to develop multi-value logic transistors with stable intermediate ... -
Threshold Voltage Modulation of a Graphene–ZnO Barristor Using a Polymer Doping Process
(Blackwell Publishing Ltd, 2019-05-06)A method to modulate the threshold voltage of a graphene–ZnO barristor is investigated. Two types of polymers, polyethyleneimine (as an n-type dopant) and poly(acrylic acid) (as a p-type dopant), are used to pre-set the ... -
A Fermi-Level-Pinning-Free 1D Electrical Contact at the Intrinsic 2D MoS₂–Metal Junction
(Wiley-VCH Verlag, 2019-05-08)Currently 2D crystals are being studied intensively for use in future nanoelectronics, as conventional semiconductor devices face challenges in high power consumption and short channel effects when scaled to the quantum ... -
The Band Structure Change of Hf₀.₅Zr₀.₅O₂/Ge System upon Post Deposition Annealing
(Elsevier B.V., 2019-05-25)Hafnium zirconium oxide films have been utilized in negative capacitance (NC) field-effect transistors (FETs). The band alignment of semiconductor and HfZrOₓ film is critical to obtain high device performance. The band ... -
First-Principles Study of Metal-Graphene Edge Contact for Ballistic Josephson Junction
(American Physical Society, 2019-06-05)Edge-contacted superconductor-graphene-superconductor Josephson junctions have been utilized to realize topological superconductivity, and have shown superconducting signatures in the quantum Hall regime. We perform ... -
In Situ Study of E-Beam Al And Hf Metal Deposition on Native Oxide InP (100)
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 ... -
Phase Stability of Li-Mn-O Oxides as Cathode Materials for Li-ion Batteries: Insights from ab initio Calculations
In this work, we present a density-functional theory (DFT) investigation of the phase stability, electrochemical stability and phase transformation mechanisms of the layered and over-lithiated Mn oxides. This study includes ... -
α-MnO₂ Nanowire Catalysts with Ultra-High Capacity and Extremely Low Overpotential in Lithium-Air Batteries through Tailored Surface Arrangement
We here report on very high capacity (11000 mA h g⁻¹), superb rate capability (4500 mA h g⁻¹ at 5000 mA g⁻¹) and high reversibility of Li-air batteries using α-MnO₂ NW catalysts mainly associated with their relatively large ... -
Modulation of Contact Resistance between Metal and Graphene by Controlling the Graphene Edge, Contact Area, and Point Defects: An Ab Initio Study
A systematic first-principles non-equilibrium Green's function study is conducted on the contact resistance between a series of metals (Au, Ag, Pt, Cu, Ni, and Pd) and graphene in the side contact geometry. Different factors ... -
MoS₂ Functionalization for Ultra-Thin Atomic Layer Deposited Dielectrics
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 ... -
Electrode-Electrolyte Interface for Solid State Li-Ion Batteries: Point Defects and Mechanical Strain
In this work, we present an ab-initio investigation of point defects in solid electrolyte γ-Li₃PO₄ and in negative electrode-electrolyte interface (Li/γ-Li₃PO₄). Our results on Li defects on γ-Li₃PO₄ exhibit that Li ...