A5084418443- Graphene research and applications
- Semiconductor materials and devices
- Ferroelectric and Negative Capacitance Devices
- Advanced Memory and Neural Computing
- 2D Materials and Applications
- Quantum and electron transport phenomena
- Carbon Nanotubes in Composites
- Advancements in Battery Materials
- MXene and MAX Phase Materials
- Ferroelectric and Piezoelectric Materials
- Advancements in Semiconductor Devices and Circuit Design
- Molecular Junctions and Nanostructures
- Mechanical and Optical Resonators
- Electronic and Structural Properties of Oxides
- Nanowire Synthesis and Applications
- Advanced Sensor and Energy Harvesting Materials
- Surface and Thin Film Phenomena
- Topological Materials and Phenomena
- Quantum Dots Synthesis And Properties
- Copper Interconnects and Reliability
- Advanced Materials and Mechanics
- Advanced Battery Technologies Research
- ZnO doping and properties
- Semiconductor materials and interfaces
- Ga2O3 and related materials
Samsung (South Korea)
2015-2024
Samsung Advanced Institute of Technology (South Korea)
2024
Seoul National University
2006-2022
Seoul Media Institute of Technology
2022
Suwon Research Institute
2018
Ajou University
2018
Samsung (Japan)
2015
California Institute of Technology
2005-2007
Despite several years of research into graphene electronics, sufficient on/off current ratio I(on)/I(off) in transistors with conventional device structures has been impossible to obtain. We report on a three-terminal active device, variable-barrier "barristor" (GB), which the key is an atomically sharp interface between and hydrogenated silicon. Large modulation (on/off 10(5)) achieved by adjusting gate voltage control graphene-silicon Schottky barrier. The absence Fermi-level pinning at...
Abstract Concepts of non-volatile memory to replace conventional flash have suffered from low material reliability and high off-state current, the use a thick, rigid blocking oxide layer in further restricts vertical scale-up. Here, we report two-terminal floating gate memory, tunnelling random access fabricated by monolayer MoS 2 /h-BN/monolayer graphene stack. Our device uses electrode for current flow channel simultaneously charging discharging through h-BN barrier. By effective charge...
Continuous advancement in nonvolatile and morphotropic beyond-Moore electronic devices requires integration of ferroelectric semiconductor materials. The emergence hafnium oxide (HfO2)-based ferroelectrics that are compatible with atomic-layer deposition has opened interesting promising avenues research. However, the origins ferroelectricity pathways to controlling it HfO2 still mysterious. We demonstrate local helium (He) implantation can activate these possible competing mechanisms,...
Ferroelectric hafnium and zirconium oxides have undergone rapid scientific development over the last decade, pushing them to forefront of ultralow-power electronic systems. Maximizing potential application in memory devices or supercapacitors these materials requires a combined effort by community address technical limitations, which still hinder their application. Besides favorable intrinsic material properties, HfO2–ZrO2 face challenges regarding endurance, retention, wake-up effect, high...
With the motivation of realizing an all graphene-based circuit for low power, we present a reliable nonvolatile graphene memory device, single-layer (SLG) ferroelectric field-effect transistor (FFET). We demonstrate that exfoliated can be optically visible on lead-zirconate-titanate (PZT) substrate and observe large window is nearly equivalent to hysteresis PZT at operating voltages in FFET. In comparison graphene, FFETs fabricated with chemical vapor deposited (CVD) exhibit enhanced...
The rectifying Schottky characteristics of the metal-semiconductor junction with high contact resistance have been a serious issue in modern electronic devices. Herein, we demonstrated conversion nature Ni-Si junction, one most commonly used junctions, into an Ohmic low by inserting single layer graphene. achieved from incorporating graphene was about 10(-8) ~ 10(-9) Ω cm(2) at Si doping concentration 10(17) cm(-3).
Abstract Ferroelectric materials offer a low‐energy, high‐speed alternative to conventional logic and memory circuitry. Hafnia‐based films have achieved single‐digit nm ferroelectricity, enabling further device miniaturization. However, they can exhibit nonideal behavior, specifically wake‐up fatigue effects, leading unpredictable performance variation over consecutive electronic switching cycles, preventing large‐scale commercialization. The origins are still under debate. Using...
Carrier density and temperature-dependent resistivity of graphene grown by chemical vapor deposition (CVD) is investigated. We observe in low mobility CVD device a generic insulating behavior at temperatures, eventually metallic high manifesting nonmonotonic temperature dependent resistivity. This feature strongly affected carrier modulation with the low-density samples exhibiting insulating-like dependence up to higher temperatures than corresponding high-density samples. To explain...
Graphene heterostructures in which graphene is combined with semiconductors or other layered 2D materials are of considerable interest, as a new class electronic devices has been realized. Here we propose technology platform based on graphene-thin-film-semiconductor-metal (GSM) junctions, can be applied to large-scale and power-efficient electronics compatible variety substrates. We demonstrate wafer-scale integration vertical field-effect transistors (VFETs) graphene-In-Ga-Zn-O (IGZO)-metal...
Piezoelectricity of transition metal dichalcogenides (TMDs) under mechanical strain has been theoretically and experimentally studied. Powerful sensors using Schottky barrier variation in TMD/metal junctions as a result the strain-induced lattice distortion associated ion-charge polarization were demonstrated. However, nearly fixed work function electrodes limits range barrier. We demonstrate highly sensitive sensor variable MoS2/graphene heterostructure field effect transistor (FET). The...
Abstract Vertical integration of 2D layered materials to form van der Waals heterostructures (vdWHs) offers new functional electronic and optoelectronic devices. However, the mobility in vertical carrier transport vdWHs field‐effect transistor (VFET) is not yet investigated spite importance for successful application VFETs integrated circuits. Here, VFET under different drain biases, gate metal work functions first engineered. The traps WSe 2 are main source scattering, which influences...
Abstract The downscaling of the capacitance equivalent oxide thickness (CET) a gate dielectric film with high constant, such as atomic layer deposited (ALD) HfO 2 , is fundamental challenge in achieving high-performance graphene-based transistors low leakage current. Here, we assess application various surface modification methods on monolayer graphene sheets grown by chemical vapour deposition to obtain uniform and pinhole-free ALD substantially small CET at wafer scale. effects...
Using first-principles calculations of graphene having high-symmetry distortion or defects, we investigate band gap opening by chiral symmetry breaking, intervalley mixing, in and show an intuitive picture understanding the terms local bonding antibonding hybridizations. We identify that breaking honeycomb lattices is ideal two-dimensional (2D) extension Peierls metal−insulator transition 1D linear lattices. spontaneous Kekule distortion, a 2D version takes place biaxially strained graphene,...
Scanning tunneling microscopy (STM) and density functional theory (DFT) calculations were used to investigate the surface morphology electronic structure of graphene synthesized on Cu by low temperature chemical vapor deposition (CVD). Periodic line patterns originating from arrangements carbon atoms passivate interaction between metal substrate graphene, resulting in flawless inherent band pristine graphene/Cu. The effective elimination states passivation is expected contribute growth...
Ferroelectric Field-Effect Transistors Because of their simple structure and operation scheme based on characteristic spontaneous polarization, ferroelectric field-effect-transistors (FeFETs), which are reviewed by Jinseong Heo, Min Hyuk Park, co-workers in article number 2204904, considered promising for ultrahigh-density information storage with high speed power efficiency. A post-3D-NAND the FeFET is shown.
In this work, we report sub-ns polarization switching in highly scaled 25 nm ferroelectric (FE) FinFET with Hf <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sub> Zr O xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (HZO) (FE)/SiO dielectric (DE) gate stack for high performance CPU application the first time. Observed limited endurance was attributed to increase of trap density stack, which quantitatively analyzed upon program/erase...
HfO2-based ferroelectrics are highly expected to lead the new paradigm of nanoelectronic devices owing their unexpected ability enhance ferroelectricity in ultimate thickness scaling limit (≤2 nm). However, an understanding its physical origin remains uncertain because direct microstructural and chemical characterization such a regime is extremely challenging. Herein, we solve mystery for continuous retention high ultrathin hafnium zirconium oxide (HZO) film (∼2 nm) by unveiling evolution...
This study provides comprehensive analysis of the structure–performance relationships in cantilever-type piezoelectric energy harvesters. It full understanding effect all practical global control variables on harvester performance. The considered for were material parameters, areal and volumetric dimensions, configuration inactive active layers. Experimentally, output power density was maximum when shape beam close to a square constant bending stiffness fixed area. Through analytical...
Atomically thin two-dimensional (2D) materials range from semimetallic graphene to insulating hexagonal boron nitride semiconducting transition-metal dichalcogenides. Recently, metal-insulator-semiconductor field effect transistors built these 2D elements were studied for flexible and transparent electronics. However, induce ambipolar characteristics alternative power-efficient circuitry, ion-gel gating is often employed high capacitive coupling, limiting stable operation at ambient...