A5067239685- 2D Materials and Applications
- Semiconductor materials and devices
- Graphene research and applications
- Advancements in Semiconductor Devices and Circuit Design
- MXene and MAX Phase Materials
- Advanced Memory and Neural Computing
- Ferroelectric and Negative Capacitance Devices
- Nanowire Synthesis and Applications
- Semiconductor materials and interfaces
- Electronic and Structural Properties of Oxides
- Perovskite Materials and Applications
- Copper Interconnects and Reliability
- Integrated Circuits and Semiconductor Failure Analysis
- Plasma Diagnostics and Applications
- Molecular Junctions and Nanostructures
- Silicon Nanostructures and Photoluminescence
- Chalcogenide Semiconductor Thin Films
- Advanced Surface Polishing Techniques
- Quantum and electron transport phenomena
- Diamond and Carbon-based Materials Research
- Metal and Thin Film Mechanics
- Phase-change materials and chalcogenides
- Conducting polymers and applications
- Ion-surface interactions and analysis
- Advanced Sensor and Energy Harvesting Materials
Sungkyunkwan University
2016-2025
Samsung (South Korea)
2002-2022
Government of the Republic of Korea
2019
Suwon Research Institute
2019
National University of Singapore
2001-2007
University System of Taiwan
2005
National Yang Ming Chiao Tung University
2005
Singapore Science Park
2002
Rensselaer Polytechnic Institute
1990-1994
Atomically thin forms of layered materials, such as conducting graphene, insulating hexagonal boron nitride (hBN), and semiconducting molybdenum disulfide (MoS2), have generated great interests recently due to the possibility combining diverse atomic layers by mechanical "stacking" create novel materials devices. In this work, we demonstrate field-effect transistors (FETs) with MoS2 channels, hBN dielectric, graphene gate electrodes. These devices show mobilities up 45 cm(2)/Vs operating...
A high-performance novel photodetector is demonstrated, which consists of graphene and CH3 NH3 PbI3 perovskite layers. The resulting hybrid exhibits a dramatically enhanced photo responsivity (180 A/W) effective quantum efficiency (5× 10(4) %) over broad bandwidth within the UV visible ranges.
Electrical metal contacts to two-dimensional (2D) semiconducting transition dichalcogenides (TMDCs) are found be the key bottleneck realization of high device performance due strong Fermi level pinning and contact resistances (Rc). Until now, monolayer TMDCs has been reported only theoretically, although that bulk experimentally. Here, we report experimental study on MoS2 MoTe2 by interpreting thermionic emission results. We also quantitatively compared our results with theoretical...
This paper demonstrates a technique to form lateral homogeneous 2D MoS2 p-n junction by partially stacking h-BN as mask p-dope MoS2. The fabricated with asymmetric electrodes of Pd and Cr/Au displayed highly efficient photoresponse (maximum external quantum efficiency ∼7000%, specific detectivity ∼5 × 10(10) Jones, light switching ratio ∼10(3)) ideal rectifying behavior. enhanced generation open-circuit voltage (VOC) short-circuit current (ISC) were understood originate from the formation...
A highly stretchable hybrid nanogenerator has been developed using a micro-patterned piezoelectric polymer P(VDF-TrFE), PDMS-CNT composite, and graphene nanosheets. Mechanical thermal energies are simultaneously harvested from single cell of the device. The exhibits high robustness behavior even after 30% stretching generates very stable pyroelectric power outputs due to micro-pattern designing.
Semiconducting 2D crystals are currently receiving significant attention due to their great potential be an ultra-thin body for efficient electrostatic modulation which enables overcome the limitations of silicon technology. Here we report that, as a key building block semiconductor devices, vertical p-n junctions fabricated in ultrathin MoS2 by introducing AuCl3 and benzyl viologen dopants. Unlike usual unipolar MoS2, show (i) ambipolar carrier transport, (ii) current rectification via...
A high-performance multilayer MoS2 p-type field-effect transistor is realized via controllable chemical doping, which shows an excellent on/off ratio of 109 and a maximum hole mobility 132 cm2 V−1 s−1 at 133 K. The developed technique will enable 2D materials to be used for future high-efficiency low-power semiconductor device applications. As service our authors readers, this journal provides supporting information supplied by the authors. Such are peer reviewed may re-organized online...
Turning many into one Single-crystal metal foils are valuable for their surface properties that allow synthesis of materials like graphene. Jin et al. present a strategy creating colossal single-crystal called “contact-free annealing” (see the Perspective by Rollett). The method relies on hanging and heating commercially available, inexpensive, cold-rolled foils. Almost as if magic, polycrystalline grains rotate anneal large sheet with specific crystal orientation. allows creation much...
A systematic modulation of the carrier type in molybdenum ditelluride (MoTe2 ) field-effect transistors (FETs) is described, through rapid thermal annealing (RTA) under a controlled O2 environment (p-type modulation) and benzyl viologen (BV) doping (n-type modulation). Al2 O3 capping then introduced to improve mobilities device stability. MoTe2 found be ultrasensitive at elevated temperatures (250 °C). Charge carriers flakes annealed via RTA various vacuum levels are tuned between...
Diverse diode characteristics were observed in two-dimensional (2D) black phosphorus (BP) and molybdenum disulfide (MoS2) heterojunctions. The of a backward rectifying diode, Zener forward obtained from the heterojunction through thickness modulation BP flake or back gate modulation. Moreover, tunnel with precursor to negative differential resistance can be realized by applying dual gating solid polymer electrolyte layer as top dielectric material. Interestingly, steep subthreshold swing 55...
Abstract Two-dimensional (2D) materials hold great promise for future nanoelectronics as conventional semiconductor technologies face serious limitations in performance and power dissipation technology nodes. The atomic thinness of 2D enables highly scaled field-effect transistors (FETs) with reduced short-channel effects while maintaining high carrier mobility, essential high-performance, low-voltage device operations. richness their electronic band structure opens up the possibility using...
Fast-growth of single crystal monolayer graphene by CVD using methane and hydrogen has been achieved on "homemade" Cu/Ni(111) alloy foils over large area. Full coverage was in 5 min or less for a particular range composition (1.3 at.% to 8.6 Ni), as compared 60 pure Cu(111) foil under identical growth conditions. These are the bulk atomic percentages Ni, superstructure at surface these with stoichiometry Cu6Ni1 (for 1.3 7.8 Ni foil) discovered low energy electron diffraction (LEED). Complete...
Currently 2D crystals are being studied intensively for use in future nanoelectronics, as conventional semiconductor devices face challenges high power consumption and short channel effects when scaled to the quantum limit. Toward this end, achieving barrier-free contact semiconductors has emerged a major roadblock. In contacts bulk metals, Fermi levels become pinned inside bandgap, deviating from ideal Schottky-Mott rule resulting significant suppression of carrier transport device. Here,...
Abstract To date, thousands of publications have reported chemical vapor deposition growth “single layer” graphene, but none them has described truly single layer graphene over large area because a fraction the adlayers. It is found that amount subsurface carbon (leading to additional nuclei) in Cu foils directly correlates with extent adlayer growth. Annealing hydrogen gas atmosphere depletes foil. Adlayer‐free crystal and polycrystalline films are grown on Cu(111) containing no carbon,...
A gate-controlled metal-semiconductor barrier modulation and its effect on carrier transport were investigated in two-dimensional (2D) transition metal dichalcogenide (TMDC) field transistors (FETs). strong photoresponse was observed both unipolar MoS2 ambipolar WSe2 FETs (i) at the high drain voltage due to a electric along channel for separating photo-excited charge carriers (ii) certain gate optimized barriers collection of contacts. The effective height between Ti/Au TMDCs estimated by...
Two-dimensional transition-metal dichalcogenides (TMDs) are unique candidates for the development of next-generation electronic devices. However, large contact resistance between metal and monolayer TMDs have significantly limited devices' performance. Also, integration ultrathin high-k dielectric layers with remains difficult due to lack dangling bonds on surface TMDs. We present molybdenum disulfide field-effect transistors bottom local gates consisting graphene. The atomic-level thickness...
This study illustrates the nature of electronic transport and its transition from one mechanism to another between a metal electrode MoS2 channel interface in field effect transistor (FET) device. Interestingly, measurements contact resistance (Rc) as function temperature indicate carrier across energy barrier thermionic emission at high tunneling low temperature. Furthermore, temperature, behavior is ascertained by current-voltage dependency that helps us feature direct bias Fowler-Nordheim...
Folded graphene in which two layers are stacked with a twist angle between them has been predicted to exhibit unique electronic, thermal, and magnetic properties. We report the folding of single crystal monolayer film grown on Cu(111) substrate by using tailored having hydrophobic region hydrophilic region. Controlled delamination from was used prepare macroscopic folded good uniformity millimeter scale. This process create many sheets each defined sheets. By identifying original lattice...
The generation of a photocurrent from two-dimensional tungsten disulfide (WS2) field-effect transistors is examined here, and its dependence on the photon energy characterized. We found WS2 devices that significant enhancement in ratio illuminated current against dark (Iillum/Idark) ∼102–103 attained, even with application electric fields ED = 0.02 EG −22 mV/nm, which are much smaller than bulk MoS2 phototransistor. Most importantly, we demonstrate our multilayer shows an extremely high...
An unconventional phase-change memory (PCM) made of In2 Se3 , which utilizes reversible phase changes between a low-resistance crystalline β and high-resistance γ is reported for the first time. Using PCM with layered film exfoliated from crystals on graphene bottom electrode, it shown that SET/RESET programmed states form via formation/annihilation periodic van der Waals' (vdW) gaps (i.e., virtual vacancy layers) in stack atomic layers concurrent reconfiguration In Se atoms across layers....