Anisotropic Electron Mobility and Contact Resistance of β-GaO Obtained via Radio Frequency Transmission Line Methods on Schottky Devices.

Monoclinic semiconducting β-GaO has drawn attention, particularly because its thin film could be achieved via mechanical exfoliation from bulk crystals, which is analogous to van der Waals materials' behavior. For the transistor devices with exfoliated β-GaO, the channel direction becomes [010] for in-plane electron transport, which changes to vertical [100] near the source/drain (S/D) contact. Hence, anisotropic transport behavior is certainly worth to study but rarely reported.

Investigation on Contact Properties of 2D van der Waals Semimetallic 1T-TiS/MoS Heterojunctions.

Two-dimensional transition metal dichalcogenides (2D TMDCs) are considered promising alternatives to Si as channel materials because of the possibility of retaining their superior electronic transport properties even at atomic body thicknesses. However, the realization of high-performance 2D TMDC field-effect transistors remains a challenge owing to Fermi-level pinning (FLP) caused by gap states and the inherent high Schottky barrier height (SBH) within the metal contact and channel layer. This study demonstrates that high-quality van der Waals (vdW) heterojunction-based contacts can be formed by depositing semimetallic TiS onto monolayer (ML) MoS.

Negative Photoresponse Switching via Electron-Hole Recombination at The Type III Junction of MoTe Channel/SnS Top Layer.

Extensive study on 2D van der Waals (vdW) heterojunctions has primarily focused on PN diodes for fast-switching photodetection, while achieving the same from 2D channel phototransistors is rare despite their other advantages. Here, a high-speed phototransistor featuring a type III junction between p-MoTe channel and n-SnS top layer is designed. The photodetecting device operates with a basis of negative photoresponse (NPR), which originates from the recombination of photoexcited electrons in n-SnS and accumulated holes in the p-MoTe channel.

Ultrafast van der Waals diode using graphene quantum capacitance and Fermi-level depinning.

Graphene, with superior electrical tunabilities, has arisen as a multifunctional insertion layer in vertically stacked devices. Although the role of graphene inserted in metal-semiconductor junctions has been well investigated in quasi-static charge transport regime, the implication of graphene insertion at ultrahigh frequencies has rarely been considered. Here, we demonstrate the diode operation of vertical Pt/n-MoSe/graphene/Au assemblies at ~200-GHz cutoff frequency (f).

Near-Infrared Self-Powered Linearly Polarized Photodetection and Digital Incoherent Holography Using WSe/ReSe van der Waals Heterostructure.

Polarization-sensitive photodetection has attracted considerable attention as an emerging technology for future optoelectronic applications such as three-dimensional (3D) imaging, quantum optics, and encryption. However, traditional photodetectors based on Si or III-V InGaAs semiconductors cannot directly detect polarized light without additional optical components. Herein, we demonstrate a self-powered linear-polarization-sensitive near-infrared (NIR) photodetector using a two-dimensional WSe/ReSe van der Waals heterostructure.

Ambipolar Channel p-TMD/n-Ga O Junction Field Effect Transistors and High Speed Photo-sensing in TMD Channel.

Highly crystalline 2D/3D-mixed p-transition metal dichalcogenide (TMD)/n-Ga O heterojunction devices are fabricated by mechanical exfoliation of each p- and n-type material. N-type β-Ga O and p-type TMD separately play as a channel for junction field effect transistors (JFETs) with each type of carriers as well as materials for a heterojunction PN diode. The work thus mainly focuses on such ambipolar channel transistors with two different types of channel in a single device architecture.

Dramatic Reduction of Contact Resistance via Ultrathin LiF in Two-Dimensional MoS Field Effect Transistors.

Molybdenum disulfide (MoS) has been regarded as one of the most important n-type two-dimensional (2D) transition metal dichalcogenide semiconductors for nanoscale electron devices. Relatively high contact resistance () remains as an issue in the 2D-devices yet to be resolved. Reliable technique is very compelling to practically produce low values in device electronics, although scientific approaches have been made to obtain a record-low .

High-Performance van der Waals Junction Field-Effect Transistors Utilizing Organic Molecule/Transition Metal Dichalcogenide Interface.

Two-dimensional (2D) transition metal dichalcogenide (TMD) hetero PN junctions with a van der Waals (vdW) interface have received much attention, because PN diodes are basically important to control the vertical current across the junction. Interestingly, the same vdW PN junction structure can be utilized for junction field-effect transistors (JFETs) where in-plane current is controlled along the junction. However, 2D vdW JFETs seem rarely reported, despite their own advantages to achieve when good vdW junction is secured.

How are Baby Boomers Different from Older Adults in Terms of Their E-Government Services Use in South Korea?

E-government services have emerged and expanded for the last decades. The digitalization of social services presents both an opportunity and a challenge to the aging population who are effectively digital immigrants. This study examined socioeconomic factors associated with e-government services awareness and usage among the aging population, with a focus on the comparison between baby boomers and older adults.

Ultrafast 27 GHz cutoff frequency in vertical WSe Schottky diodes with extremely low contact resistance.

Ultra-thin two-dimensional semiconducting crystals in their monolayer and few-layer forms show promising aspects in nanoelectronic applications. However, the ultra-thin nature of two-dimensional crystals inevitably results in high contact resistance from limited channel/contact volume as well as device-to-device variability, which seriously limit reliable applications using two-dimensional semiconductors. Here, we incorporate rather thick two-dimensional layered semiconducting crystals for reliable vertical diodes showing excellent Ohmic and Schottky contacts.

Piperine protects cisplatin-induced apoptosis via heme oxygenase-1 induction in auditory cells.

Piperine is a major component of black pepper, Piper nigrum Linn, used widely in traditional medicine. In this study, we examined whether piperine could protect House Ear Institute-Organ of Corti 1 (HEI-OC1) cells against cisplatin-induced apoptosis through the induction of heme oxygenase (HO)-1 expression. Piperine (10-100 microM) induced the expression of HO-1 in dose- and time-dependent manners.

The effect of a fibrin-fibronectin/beta-tricalcium phosphate/recombinant human bone morphogenetic protein-2 system on bone formation in rat calvarial defects.

In spite of good prospects for bone morphogenetic proteins (BMP) applications, an ideal carrier system for BMPs has not yet been identified. The purpose of this study was to evaluate the osteogenic effect of a fibrin-fibronectin sealing system (FFSS) combined with beta-tricalcium phosphate (beta-TCP) as a carrier system for recombinant human bone morphogenetic proteins (rhBMP-2) in the rat calvarial defect model. Eight-millimeter critical-size calvarial defects were created in 100 male Sprague-Dawley rats.