A5073755121- 2D Materials and Applications
- MXene and MAX Phase Materials
- Perovskite Materials and Applications
- Thin-Film Transistor Technologies
- Nanowire Synthesis and Applications
- Semiconductor materials and devices
- ZnO doping and properties
- Ferroelectric and Piezoelectric Materials
- Electronic and Structural Properties of Oxides
- Advanced Sensor and Energy Harvesting Materials
- Silicon Nanostructures and Photoluminescence
- Microwave Dielectric Ceramics Synthesis
- Semiconductor materials and interfaces
- Chalcogenide Semiconductor Thin Films
- Multiferroics and related materials
- Magnetic and transport properties of perovskites and related materials
- Graphene research and applications
- Conducting polymers and applications
- Ferroelectric and Negative Capacitance Devices
- Silicon and Solar Cell Technologies
- Gas Sensing Nanomaterials and Sensors
- Organic Electronics and Photovoltaics
- Advanced ceramic materials synthesis
- Semiconductor Lasers and Optical Devices
- Quantum Dots Synthesis And Properties
Kookmin University
2015-2024
National Institute of Technology, Gunma College
2021
Government of the Republic of Korea
2020
Chonnam National University
2012-2019
Sungkyunkwan University
2019
University of California, Berkeley
2000-2012
Samsung (South Korea)
2009-2012
Pohang University of Science and Technology
2010
Los Alamos National Laboratory
2005-2007
Applied Materials (United States)
2007
Phototransistors based on multilayer MoS2 crystals are demonstrated with a wider spectral response and higher photoresponsivity than single-layer phototransistors. Multilayer phototransistors further exhibit high room temperature mobilities (>70 cm2V−1s−1), near-ideal subthreshold swings (∼70 mV decade−1), low operating gate biases (<5 V), negligible shifts in the threshold voltages during illumination. Detailed facts of importance to specialist readers published as "Supporting Information"....
A low-power flexible organic light-emitting diode (OLED) display device based on low temperature color filters with a thin film encapsulated RGB OLED microcavity is achieved high contrast ratios (up to 150 000:1 in dark ambient) and power consumption (34% saving compared polarization film). Furthermore, mechanical 10 000 times folding experiment radius of 1 mm demonstrates the reliability device.
Abstract We present a MoS 2 biosensor to electrically detect prostate specific antigen (PSA) in highly sensitive and label-free manner. Unlike previous -FET-based biosensors, the device configuration of our biosensors does not require dielectric layer such as HfO due hydrophobicity . Such an oxide-free operation improves sensitivity simplifies sensor design. For quantitative selective detection PSA antigen, anti-PSA antibody was immobilized on surface. Then, introduction into surface...
Abstract Enhanced performance of an inverted‐type polymer solar cell is reported by controlling the surface energy a zinc oxide (ZnO) buffer layer, on which photoactive layer composed polymer:fullerene‐derivative bulk heterojunction formed. With approach based mixed self‐assembled monolayer, ZnO can be controlled between 40 mN m −1 and 70 with negligible changes in its work function. For given range power conversion efficiency increases from 3.27% to 3.70% through enhanced photocurrents. The...
We report on the effect of oxygen plasma treatment two-dimensional multilayer MoS2 crystals subsequent growth Al2O3 and HfO2 films, which were formed by atomic layer deposition (ALD) using trimethylaluminum tetrakis-(ethylmethylamino)hafnium metal precursors, respectively, with water oxidant. Due to formation an ultrathin Mo-oxide surface, surface coverage films was significantly improved compared those pristine MoS2, even at a high ALD temperature. These results indicate that modification...
Local-gate multilayer MoS2 phototransistors exhibit a photoresponsivity of up to 342.6 A W−1, which is higher by 3 orders magnitude than that global-gate phototransistors. These simulations indicate the gate underlap critical for enhancement photoresponsivity. results suggest high can be achieved in indirect-bandgap optimizing optoelectronic design.
We report the interface properties of atomic-layer-deposited Al2O3 thin films on ultraviolet/ozone (UV/O3)-treated multilayer MoS2 crystals. The formation S-O bonds after low-power UV/O3 treatment increased surface energy, allowing subsequent deposition uniform films. capacitance-voltage measurement Au-Al2O3-MoS2 metal oxide semiconductor capacitors indicated n-type with an electron density ∼10(17) cm(-3) and a minimum trap ∼10(11) cm(-2) eV(-1). These results demonstrate possibility forming...
This paper presents ultrathin and highly sensitive input/output devices consisting of a capacitive touch sensor (Cap-TSP) integrated on thin-film-encapsulated active-matrix organic light-emitting diodes (OLEDs). The optimal structure the electrically noise-free sensor, which is assembled OLED (AMOLED) display, obtained by investigating internal electrical field distribution capacitance change based Q3D Extractor model. Electrostatic simulations have verified malfunction-free signals for 4-in...
We report the synthesis of large-area monolayer MoSe<sub>2</sub> films extended up to a millimeter scale on SiO<sub>2</sub>/Si substrates by atmospheric pressure chemical vapor deposition (CVD).
There is a great interest in phototransistors based on transition metal dichalcogenides because of their interesting optoelectronic properties. However, most emphasis has been put MoS2 and little attention given to MoSe2, which higher optical absorbance. Here, we present compelling case for multilayer MoSe2 fabricated bottom-gate thin-film transistor configuration SiO2/Si substrates. Under 650-nm-laser, our phototransistor exhibited the best performance among literature, including highest...
We report the largest-size thin films of uniform single-layer MoS2 on sapphire substrates grown by chemical vapor deposition based reaction gaseous MoO3 and S evaporated from solid sources. The as-grown were continuous in thickness for more than 4 cm without existence triangular-shaped clusters. Compared to mechanically exfoliated crystals, possessed consistent valence states crystal structure along with strong photoluminescence emission optical absorbance at high energy. These results...
The stability of hafnium indium zinc oxide thin film transistors under negative bias stress with simultaneous exposure to white light was evaluated. Two different inverted staggered bottom gate devices, each a silicon and nitride passivation, were compared. latter exhibits higher field effect mobility but inferior subthreshold swing, undergoes more severe shifts in threshold voltage (VT) during illumination stress. time evolution VT fits the stretched exponential equation, which implies that...
We investigated the dependence of electron mobility on thickness MoS2 nanosheets by fabricating bottom-gate single and few-layer thin-film transistors with SiO2 gate dielectrics Au electrodes. All fabricated showed on/off-current ratio ∼107 saturated output characteristics without high-k capping layers. As increased from 1 to 6 layers, field-effect ∼10 ∼18 cm2V−1s−1. The subthreshold swing suggests that increase may be related contact resistance dielectric constant layer its thickness.
We report the effect of Al2O3 encapsulation on carrier mobility and contact resistance multilayer MoS2 thin-film transistors by statistically investigating 70 devices with SiO2 bottom-gate dielectric. After atomic layer deposition, calculation based Y-function method indicates that enhancement from 24.3 cm2 V−1 s−1 to 41.2 occurs independently reduction 276 kΩ·μm 118 kΩ·μm. Furthermore, contrary previous literature, we observe a negligible thermal annealing during deposition Al2O3. These...
Surface plasmon resonance (SPR) sensors based on a silver film suffer from signal degradation due to oxidation in aqueous sensing environments. To overcome this limitation, we fabricated the planar plasmonic substrate employing an atomic MoS2 layer surface. Successful production of large-area monolayer blocks penetration oxygen and water molecules. In addition, theoretically experimentally found that can improve SPR sensitivity stability significantly. study, proposed has potential provide...
In this paper, we present a simple, low-cost and flexible hybrid cell that converts individually or simultaneously low-frequency mechanical energy photon into electricity using piezoelectric zinc oxide (ZnO) in conjunction with organic solar design. Since the is designed by coupled photoconductive properties of ZnO, naturally architecture without crosstalk an additional assembling process to create multi-type scavengers, thus differing from simple integration two different generators. It...
We report the different oxidation behavior between polycrystalline chemical-vapor-deposited and mechanically exfoliated single crystal MoS2 monolayers by ultraviolet-ozone treatment. As treatment time increased from 0 to 5 min, photoluminescence emission Raman modes of both disappeared, suggesting structural degradation oxidation. Analysis with optical absorbance X-ray photoelectron spectroscopy suggested formation MoO3 in after In addition, possibly led oxygen vacancies, molybdenum...
Hexagonal boron nitride (h-BN) has been considered a promising dielectric for two-dimensional (2D) material-based electronics due to its atomically smooth and charge-free interface with an in-plane lattice constant similar that of graphene. Here, we report atomic layer deposition (ALD-BN) using BCl3 NH3 precursors directly on thermal SiO2 substrates at relatively low temperature 600 °C. The films were characterized by X-ray photoelectron spectroscopy, force microscopy, transmission electron...