https://scholar.dgist.ac.kr/handle/20.500.11750/27 2026-07-21T12:18:55Z https://scholar.dgist.ac.kr/handle/20.500.11750/60458 Title: Magnetic glass behaviors of bicontinuous nanocomposite films fabricated by partial oxidation of Pt-Ni-Co Author(s): Ha, Jae-Hyun; Cho, Beopgil; Park, Jaemun; Kim, Tae-Hwan; Park, Keeseong; Han, Dong-Soo; Hong, Jung-Il Abstract: We report the magnetic properties of metal/oxide hybrid nanocomposite thin films derived from an interpenetrating nanoscale morphology formed by reactive co-sputtering of Pt and Co0.7Ni0.3 in a controlled argon and oxygen atmosphere at room temperature. During deposition, selective oxidation of transition-metal elements of Co and Ni, in the presence of less reactive Pt, drives spontaneous phase separation into ferromagnetic (FM) metallic PtNi and antiferromagnetic (AFM) amorphous CoO nanophases. The resulting nanocomposite constitutes a highly entangled three-dimensional network of FM/AFM domains where characteristic dimensions remain in the order of approximately less than 2 nm. The resulting bicontinuous architecture facilitates dense interfacial spin couplings across the entire volume of the film. Unlike conventional exchange-biased magnetic multilayer systems, the nanocomposite exhibits markedly slow spin dynamics near the magnetic transition region, as evidenced by strong frequency dependence of AC susceptibility. This behavior is attributed to the complex magnetic energy landscape caused by the disordered distribution of AFM regions surrounding the FM phase. At lower temperatures below the blocking point, the FM PtNi phase becomes strongly exchange-coupled with the adjacent AFM CoO, leading to a magnetically frozen state. These observations indicate a re-entrant magnetic glass behavior originated from the nanoscale interfacial frustration in the spontaneously formed multiple magnetic nanophases. 2026-04-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60428 Title: 브롬 화합물의 중수소화 방법, 이에 사용되는 중수소화 용액 및 이를 이용하여 제조된 중수소화물 Author(s): 이성기; 이지인 Abstract: 본 발명은 브롬 화합물의 중수소화 방법, 이에 사용되는 중수소화 용액 및 이를 이용하여 제조된 중수소화물을 개시한다. 본 발명은 브롬 화합물, 이황화물(disulfide), 실란 화합물(silane compound), 중수(D2O) 및 용매를 혼합하여 중수소화 용액을 제조하는 단계; 가시광선 조사 하에 상기 중수소화 용액을 교반하여 중수소화물을 제조하는 단계;를 포함하는 것을 특징으로 한다. https://scholar.dgist.ac.kr/handle/20.500.11750/60422 Title: Enhanced Wide-Bandgap Perovskite Solar Cells via Kinetically Optimized C60 Electron-Transport Layers Author(s): Kumar, Naveen; Jo, Hyo Jeong; Son, Dae-Ho; Lee, Jaebaek; Ali, Amanat; Kang, Jin-Kyu; Yang, Kee-Jeong; Sung, Shi-Joon; Jeong, Hyeonjong; Cho, Chang-Hee; Kim, Dae-Hwan; Hwang, Dae-Kue Abstract: High-efficiency tandem solar cells require wide-bandgap (WBG) perovskites as the top absorber, yet such devices often suffer severe nonradiative recombination, voltage losses, and halide segregation. This work demonstrates that carefully controlling the deposition kinetics of the fullerene electron-transport layer (ETL) offers an elegant route to overcome these issues without complex passivation strategies. WBG perovskite solar cells using a FA(0)(.8)Cs(0)(.2)Pb(I0.8Br0.2)(3) absorber were fabricated in a p-i-n architecture with C-60 ETLs deposited at three different evaporation rates. When the C-60 deposition rate was slowed to 0.1 & Aring; s(-1), our devices achieve a 20.4% PCE with a relatively low Voc deficit (~0.48 eV) without complex molecular passivation, 2D/3D heterostructures, or multistep surface reconstruction. The improvement originates from suppressed nonradiative recombination and reduced shunt leakage: The slow-deposited C-60 film yields a higher open-circuit voltage (~1.17 V), increased fill factor (80%), and reduced saturation current density and trap-state density compared with faster deposition. Photoluminescence, impedance spectroscopy, and transient photovoltage analyses reveal that slower deposition produces a compact and well-ordered C-60 layer which minimizes trap-assisted recombination, decreases Urbach energy (16.68 meV), and lowers the ideality factor (n approximate to 1.33). Structural characterizations confirm improved C-60 molecular interface and smoother morphology at slow deposition rates. This work provides a simple processing guideline for high-performance WBG perovskite solar cells and offers valuable insights for scalable tandem cell fabrication. 2026-03-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60420 Title: Quantized Conductance through Surface States in High Quality Three-Dimensional Dirac Semimetal Cd3As2 Nanowire/Nanoribbon p-n Junctions Author(s): An, Sungjin; Siu, Zhuo Bin; Kaladzhyan, Vardan; Bardarson, Jens H.; Lee, Sunghun; Lee, Myoung-Jae; Park, Kidong; Park, Jeunghee; Jalil, Mansoor B. A.; Seo, Jungpil; Jung, Minkyung Abstract: We report the observation of quantized conductance in high-mobility three-dimensional Dirac semimetal Cd3As2 nanowire and nanoribbon p-n junctions. By employing suspended device geometries with dual local gates, we form tunable p-n junctions and realize ballistic transport across sub-micron channel lengths. In a wide nanoribbon device with a channel width of similar to 330 nm, conductance plateaus appear at integer multiples of 2e(2)/h in the n-n regime under high magnetic fields. Numerical simulations suggest that these features represent unresolved spin split subbands due to the smaller subband spacing in wider channels and support the interpretation that the observed quantization may originate from surface-state-dominated conduction. In contrast, narrower nanoribbons and nanowires exhibit conductance steps of 1e(2)/h, demonstrating spin-resolved subbands likely due to enhanced confinement effects. From spin-resolved subband spectroscopy, we extract an effective Land & eacute; g-factor of similar to 43 for the first subband in the bulk gap, establishing these nanostructures as a prospective platform for fault-tolerant quantum electronics. 2026-05-31T15:00:00Z