Hong Seok Oh

We introduce the concept of group social capital—the set of resources made available to a group through members' social relationships within the social structure of the group and in the broader formal and informal structure of the organization. We argue that greater group social capital resources lead to greater group effectiveness and that there are many different conduits through which group social capital resources flow. We present a multilevel, multidimensional model arguing that an optimal

Despite growing interest in social network brokerage, its psychological antecedents have been neglected. One possibility is that brokerage relates to self-monitoring personality orientation. High self-monitors, relative to low self-monitors, in adapting their self-presentations to the demands of different groups, may occupy positions as brokers between disconnected social worlds. For 162 Korean expatriate entrepreneurs in a Canadian urban area, the results showed that those high in self-monitori

We report large-scale and multiplexed tactile sensors with submillimeter-scale shear sensation and autonomous and real-time closed-loop grip adjustment. We leveraged dual-gate piezoelectric zinc oxide (ZnO) thin-film transistors (TFTs) fabricated on flexible substrates to record normal and shear forces with high sensitivity over a broad range of forces. An individual ZnO TFT can intrinsically sense, amplify, and multiplex force signals, allowing ease of scalability for multiplexing from hundreds

Heteroepitaxy of semiconductors on two-dimensional (2-d) atomic layered materials enables the use of flexible and transferable inorganic electronic and optoelectronic devices in various applications. Herein, we report the shape-and morphology-controlled van der Waals (vdW) epitaxy of ZnO nanostructures on hexagonal boron nitride (hBN) insulating layers for an architectured semiconductor integration on the 2-d layered materials. The vdW surface feature of the 2-d nanomaterials, because of the sur

Abstract The bottom‐up integration of a 1D–2D hybrid semiconductor nanostructure into a vertical field‐effect transistor (VFET) for use in flexible inorganic electronics is reported. Zinc oxide (ZnO) nanotubes on graphene film is used as an example. The VFET is fabricated by growing position‐ and dimension‐controlled single crystal ZnO nanotubes vertically on a large graphene film. The graphene film, which acts as the substrate, provides a bottom electrical contact to the nanotubes. Due to the h

We report the growth and transfer of centimeter-sized, epitaxial hexagonal boron nitride (h-BN) few-layer films using Ni(111) single-crystal substrates. The h-BN films were heteroepitaxially grown on 10 × 10 mm2 or 20 × 20 mm2 Ni(111) substrates using atmospheric pressure chemical vapor deposition with a single ammonia-borane precursor. The grown films were transferred to arbitrary substrates via an electrochemical delamination technique, and the remaining Ni(111) substrates were repeatedly re-u

) electrodes. A thorough investigation of the field-dependent persistent photoconductivity (PPC) of the Te channel revealed that the relaxation speed of the transient photocurrent depended on the gate bias. Utilizing the PPC property, the Te device served as an excellent photonic synapse under light pulse stimulus, exhibiting multiple synaptic characteristics such as excitatory postsynaptic current and paired-pulse facilitation, as well as highly linear potentiation-depression characteristics; a

Abstract We report the fabrication and characterization of indium gallium zinc oxide (IGZO)-based synaptic thin-film transistors. Radio-frequency magnetron-sputtered AlO x thin films are embedded in the IGZO channel as charge-trapping layers to provide synaptic behavior. The voltage pulse introduced at the gate electrodes traps or de-traps charges in the embedded AlO x layer thus modulates the channel current, which in turn leads to the ability to mimic biological synaptic behaviors such as exci

Piezoelectric devices transduce mechanical energy to electrical energy by elastic deformation, which distorts local dipoles in crystalline materials. Amongst electromechanical sensors, piezoelectric devices are advantageous because of their scalability, light weight, low power consumption, and readily built-in amplification and ability for multiplexing, which are essential for wearables, medical devices, and robotics. This paper reviews recent progress in active piezoelectric devices. We classif

The chemical vapor deposition of hexagonal boron nitride layers from BCl3 and NH3 is highly beneficial for scalable synthesis with high controllability, yet multiple challenges such as corrosive reaction or by-product formation have hindered its successful demonstration. Here, we report the synthesis of polycrystalline hexagonal boron nitride (h-BN) layers on copper foil using BCl3 and NH3. The sequential pulse injection of precursors leads to the formation of atomically thin h-BN layers with a

Unlike conventional fluorophores experiencing aggregation-caused quenching (ACQ) in the solid state, aggregation-induced emission (AIE) luminogens (AIEgens) exhibit enhanced fluorescence upon aggregation. This property renders AIEgens promising for various technological applications. However, developing red-emitting AIEgens with high fluorescence efficiency remains challenging due to structural constraints. Compact red-light-emitting AIEgens hold great potential, as their small, simple fluoresce

The authors report the fabrication of highly sensitive, rapidly responding flexible force sensors using ZnO/ZnMgO coaxial nanotubes grown on graphene layers and their applications in sleep apnea monitoring. Flexible force sensors are fabricated by forming Schottky contacts to the nanotube array, followed by the mechanical release of the entire structure from the host substrate. The electrical characteristics of ZnO and ZnO/ZnMgO nanotube-based sensors are thoroughly investigated and compared. Im

Despite the importance of transistors in modern electronics, transistor characterization requires expensive instruments that are not affordable for many researchers, engineers and educators. Here, we present software that can control source-meter units (SMUs) for current–voltage (I–V) characterization of field-effect transistors, bipolar junction transistors and general two-terminal devices. The software provides a graphical user interface that allows the user to perform parameter setup, real-ti