H. S. Jung

Optimization of CuO thickness in the Cu 2 O/CuO photocathode by controlling the annealing time: optimal thickness of CuO induces the improved light utilization and band bending, resulting in the enhanced photoelectrochemical performance.

Uniform, well-ordered sub-20 nm patterns can be generated by the templated self-assembly of block copolymers (BCPs) with a high Flory-Huggins interaction parameter (χ). However, the self-assembled BCP monolayers remain limited in the possible structural geometries. Here, we introduce a multiple self-assembly method which uses di-BCPs to produce diverse morphologies, such as dot, dot-in-honeycomb, line-on-dot, double-dot, pondering, dot-in-pondering, and line-on-pondering patterns. To improve the

We demonstrated the wafer level batch synthesis and fabrication of single semiconducting thermoelectric nanoribbon based devices by Lithographically Patterned Galvanic Displacement (LPGD). The shape, composition, and dimension of nanoribbons were tailored by adjusting deposition conditions. High resolution TEM images with fast Fourier transform (FFT)-converted selected area electron diffraction (SAED) patterns confirmed the formation of polycrystalline Bi2Te3 intermetallic compound with a rhombo

Single crystalline PbTe nanowires were potentiostatically electrodeposited by a template-directed method using track-etched polycarbonate membranes as scaffolds in acidic nitrate baths. They exhibited a face-centered cubic (FCC) structure with a preferred growth direction about 31° against the [200] direction. By galvanic displacing the ends of PbTe nanowire with gold prior to electrode microfabrication, the Schottky barrier (i.e., native PbTe oxide) at the interfaces between nanowire and electr

Nickel phosphide (Ni-P) films as a catalytic cathode for the hydrogen evolution reaction (HER) of a water splitting were fabricated by a pulse-reverse electrodeposition technique. The electrochemical behaviors for the electrodeposition of Ni-P were investigated by the characterization of peaks in a cyclic voltammogram. The composition of the electrodeposited Ni-P alloys was controlled by adjusting duty cycles of the pulse-reverse electrodeposition. The HER electrocatalytic properties of the Ni-P

Abstract The fabrication of freestanding bendable films without polymer substrates is demonstrated as a capacitive humidity-sensing material. The bendable and porous SiO 2 /Si films are simply prepared by electrochemical-assisted stripping, metal-assisted chemical etching, followed by oxidation procedures. The capacitive humidity-sensing properties of the fabricated porous SiO 2 /Si film are characterized as a function of the relative humidity and frequency. The remarkable sensing performance is

One-dimensional heterostructures consisting of periodically modulated bismuth telluride tube/wire were synthesized by galvanic displacement reaction of Co/Ni multi-segmented sacrificial nanowires. Utilizing the difference in redox potential and corrosion behavior of Co and Ni, segments, dimension, composition, and structure of the individual segments were also precisely engineered. The programmable ability to synthesize heterostructures with simultaneously modulation of various dimensions in amb

Millimeter-long one-dimensional Sb x Te y nanoribbons with controlled composition and dimensions (down to 16 nm) were demonstrated using lithographically patterned electrodeposition at predetermined locations. The morphology of nanoribbons was tuned by applying a pulse plating technique and addition of surfactant (i.e., CTAB) in the electrolyte. Independent of geometry, the deposit Te content decreased from 69 to 51 at. % Te with an increase in the applied potential. The electrical resistivity a

Pt-decorated In2O3 nanofibers with tailored size and morphology were synthesized as sensing materials for a highly sensitive toluene gas sensor. The bridge-type micro-platforms, including micro-heaters and micro-electrodes for the integration of In2O3 nanofibers-based sensing materials, were designed to demonstrate the sensing at high temperature with low power consumption. The gas sensing properties of the fabricated toluene gas sensor were systematically investigated by controlling the power o

. Furthermore, the device exhibited stability under both negative and positive bias stress conditions, with threshold voltage shifts of -2 V and +1.8 V, respectively. These results are attributed to the introduction of Ga, which not only reduced the electron concentration by creating holes within the Tin oxide matrix but also decreased oxygen-related defects in the film due to the strong bonding affinity of Ga with oxygen. Additionally, Ga doping suppressed crystallization in the ATO film, there