Jeong Min Baik

Exceptionally sensitive hydrogen sensors were produced using Pd-nanoparticle-decorated, single vanadium dioxide nanowires. The high-sensitivity arises from the large downward shift in the insulator to metal transition temperature following the adsorption on and incorporation of atomic hydrogen, produced by dissociative chemisorption on Pd, in the VO(2), producing approximately 1000-fold current increases. During a rapid initial process, the insulator to metal transition temperature is decreased

Ever since a new energy harvesting technology, known as a triboelectric nanogenerator (TENG), was reported in 2012, the rapid development of device fabrication techniques and mechanical system designs have considerably made the instantaneous output power increase up to several tens of mW/cm². With this innovative technology, a lot of researchers experimentally demonstrated that various portable/wearable devices could be operated without any external power. This article provides a comprehensive r

Uniform nanogaps were produced in silver nanowires previously fabricated by AC electrodeposition in porous anodic alumina templates and released by dissolving the oxide matrix. Configuring the nanowires with electrodes and passing current through them created nanogaps by electromigration. Uniform nanogaps approximately perpendicular to the axes of the nanowires were produced with widths in the range approximately 17 to approximately 40 nm. Gaps as small as 5 nm but with less uniform geometries c

Vertically well-aligned (Zn,Mn)O nanorods (see Figure) that show ferromagnetic behavior at room temperature have been grown on sapphire substrates by chemical vapor deposition. The high optical quality of the nanorods has been demonstrated by photoluminescence spectroscopy. These nanowires may find use in future nanoscale magneto-optic and magneto-electronic applications.

A dilute magnetic semiconductor was achieved by implanting Mn ions into p-type GaN and subsequent annealing. The ferromagnetic property was obtained after annealing at 800 °C. This was attributed to the formation of Ga–Mn magnetic phases. Higher temperature annealing at 900 °C reduced the ferromagnetic signal and produced antiferromagnetic Mn–N compounds such as Mn6N2.58 and Mn3N2, leaving N vacancies. This provides evidence that N vacancies play a critical role in weakening the ferromagnetic pr

Single-crystal VO2 nanowires were synthesized using atmospheric-pressure and physical vapor deposition and outfitted with electrodes for current−voltage measurements. The Mott insulator-to-metal transition temperatures of several nanowires with varying lateral dimensions were determined by measuring the voltage values at which the sharp current step, signaling that the occurrence of the insulator-to-metal or the reverse transitions, had taken place. The observed Mott transition temperatures, whi

Fe nanowires were fabricated by electrodeposition into nanoporous alumina templates grown in sulfuric and oxalic acid by a pulse electrodeposition. A 42 nm diameter Fe nano wire grown in sulfuric anodized pores is essentially a single-crystalline object that grows preferentially so as to align its (110) axis along the long axis of the pore. Its coercivity is 1654 Oe and a squareness of 0.66 for axially aligned magnetic fields. For an Fe nanowire grown in oxalic anodized pores, both (110) and (20

Abstract Eco‐friendly triboelectric nanogenerator (eco‐TENG) is considered as a next‐generation renewable kinetic energy‐harvesting technology, especially for its potential use as a power supply unit for self‐powered electronics. For eco‐TENGs, nature‐derived biomaterials, which are non‐toxic to human and environment, highly biocompatible, and abundant in nature, are used for tribopositive or tribonegative materials, or both. Here, recent progress in nature‐derived biomaterials exploited for eco

Abstract In this study, the humidity‐resistant triboelectric nanogenerators (TENGs) utilizing MoS₂‐encapsulated SiO₂ nanoparticles (NPs), aimed at enhancing self‐powered gas sensing applications, are reported. The core‐shell structure, featuring a thin MoS₂ layer uniformly grown on SiO₂, addresses common humidity‐induced performance degradation. The growth mechanism involves the decomposition and sulfidation of molybdenum species, with MoS₂ selectively nucleating on SiO₂ to form a stable, hydrop

Abstract The paper extensively explores moisture‐induced charge decay in tribo‐materials, addressing charge generation fundamentals and overcoming strategies. Triboelectric effect and contact electrification models are discussed, with corona charging and hydro‐charging as effective charge generation methods. Moisture‐induced adverse effects, such as swelling and charge dissipation, are outlined. Electronegativity and dangling bonds' roles in charge traps are explored, along with the impact of fu

Current core-shell hybrids used in diverse energy-related applications possess limited dispersibility and film uniformity that govern their overall performances. Herein, we showcase superdispersible core-shell hybrids (P2VP@BaTiO₃) composed of a poly(2-vinylpyridine) (P2VP) (5-20 wt %) and a barium titanate oxide (BaTiO₃), maximizing dielectric constants by forming the high-quality uniform films. The P2VP@BaTiO₃-based triboelectric nanogenerators (TENGs), especia

Ferromagnetic properties of (Ga,Mn)N nanowires were examined by treating with nitrogen plasma at 200 °C. Nanowires grown by chemical vapor deposition were n-type and no secondary phases were found. The magnetic moment increased and was maintained at room temperature by this treatment. Synchrotron radiation photoemission spectroscopy revealed that Ga vacancies significantly increased, but N vacancies decreased by plasma treatment, leading to a decrease of MnGa–VN complex and the enhancement of Mn

Abstract The present work demonstrates the very first approach to enhancing the output voltage of a thermoelectric generator by introducing highly charged polyimide‐based dielectrics. High charge density over 320 µC m −2 in C 60 ‐containing block polyimide (PI‐ b ‐C 60 ) having excellent charge retention characteristics is obtained through an ion injection process, attached at the cooling part of a thermoelectric generator consisting of Cu/p‐type BiSbTe/Au/Cr/SiO 2 /Si. This significantly increa