Sun-Woo Choi

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We report a significant enhancement in the gas sensing properties of In(2)O(3) nanowires by functionalizing their surfaces with Pt nanoparticles. For Pt-functionalization, In(2)O(3)-Pt core-shell nanowires are synthesized by the sputtering deposition of Pt layers on bare In(2)O(3) nanowires. Next, continuous Pt shell layers are transformed into Pt(More)
Networked SnO(2) nanowire sensors were achieved using the selective growth of SnO(2) nanowires and their tangling ability, particularly on on-chip V-groove structures, in an effort to overcome the disadvantages imposed on the conventional trench-structured SnO(2) nanowire sensors. The sensing performance of the V-groove-structured SnO(2) nanowire sensors(More)
SnO2-ZnO core-shell nanofibers were synthesized via a novel two-step process. First, SnO2 nanofibers were synthesized by electrospinning. In sequence, ZnO shell layers were deposited using atomic layer deposition on the electrospinning synthesized SnO2 nanofibers. To demonstrate the practical applications of the synthesized core-shell nanofibers, we(More)
γ-ray radiolysis is applied to synthesizing Pd nanodots on networked SnO(2) nanowires. The growth behavior of Pd nanodots is systematically investigated as a function of the precursor concentration, illumination intensity, and exposure time of the γ-rays. These factors greatly influence the growth behavior of the Pd nanodots. Selectively grown networked(More)
γ-Ray radiolysis was applied to the synthesis of Au nanoparticles. The growth behavior of Au nanoparticles was systematically investigated as a function of the processing parameters under γ-ray radiolysis. The surface of the networked SnO(2) nanowires fabricated through the vapor-phase selective growth process was uniformly functionalized with the Au(More)
Selectively-grown networked SnO2 nanowires were functionalized with Pt nanodots by the radiolysis process. NO2 sensing characteristics of Pt-functionalized SnO2 nanowires were compared with those of bare SnO2 nanowires. The results demonstrate that the Pt functionalization greatly enhances the sensitivity and response time in SnO2 nanowire-based gas(More)
We report a dual functional sensing mechanism for ultrasensitive chemoresistive sensors based on SnO2-ZnO core-shell nanowires (C-S NWs) for detection of trace amounts of reducing gases. C-S NWs were synthesized by a two-step process, in which core SnO2 nanowires were first prepared by vapor-liquid-solid growth and ZnO shell layers were subsequently(More)
We report, and propose a mechanism for, the exceptional hydrogen gas (H2) sensing ability of ZnO nanofibers. In comparison to SnO2 nanofibers, ZnO nanofibers show outstanding H2 gas response and unmistakable H2 selectivity. Different from the reducing gas effect observed in SnO2 nanofibers, a semiconductor-to-metal transition that occurs in the presence of(More)
We report a novel method for fabricating a highly sensitive chemical sensor based on a ZnO nanorod array that is epitaxially grown on a Pt-coated Si substrate, with a top–top electrode configuration. To practically test the device, its O2 and NO2 sensing properties were investigated. The gas sensing properties of this type of device suggest that the(More)
Networked ZnO nanowires were fabricated via a vapor-phase selective growth method. Pt nanoparticles were functionalized on the networked ZnO nanowires. In this study, for the functioanlization, γ-ray radiolysis was applied. By the method, Pt nanoparticles of - 10 nm in diameter were uniformly anchored on the surface of each ZnO nanowire. The sensing(More)