Chae Ok Kim
Hanyang University · 工学
研究室紹介
Professor Chae Ok Kim's research lab specializes in the development and characterization of advanced thin-film materials for next-generation electronic and optoelectronic applications. Key research directions include low-temperature crystallization of amorphous silicon via metal-induced crystallization (MIC) for high-performance poly-Si thin-film transistors, synthesis of luminescent nanophosphors using microemulsion techniques, and the growth of functional oxide films such as half-metallic Fe3O4 at room temperature. The lab also investigates the role of external fields and nanostructure engineering in enhancing crystallization kinetics and material properties.
Research Overview
Research Output Trend
Figures are computed from collected data and may differ slightly.
Selected Papers
15Amorphous silicon (a-Si) was crystallized by metal-induced crystallization (MIC) using a Ni standard absorption solution. The a-Si films spin-coated with a 5000 ppm Ni solution were crystallized at as low as 500 °C. Needlelike morphology, developed as a result of the migration of NiSi2 precipitates, appears in the MIC poly-Si. The growth of the needlelike crystallites proceeds to a direction parallel to 〈111〉. The a-Si can be fully crystallized at 500 °C for 20 h.
Amorphous silicon (a-Si) was crystallized by metal induced crystallization (MIC) in an electric field. A 2 nm Ni layer on a-Si was used for the crystallization. The MIC temperature can be reduced to 380 °C in an electric field of 360 V/cm. The Ni-MIC poly-Si has a crystalline volume fraction of 92% with an average grain size of ∼150 nm. The fact that the crystallization temperature can be reduced appears to be due to the enhancement of NiSi2 migration through a-Si in an electric field.
Half-metallic Fe3O4 films were prepared at room temperature using a rf sputtering system specially integrated with an external rf source. Primary emphasis was placed on obtaining a large amount of active oxygen radicals through an external electrode for efficient deposition. The insertion of an external electrode was found to be critical for room temperature growth of Fe3O4 thin films. The structural and electrical properties gave shift and broadening effects to the Verwey temperature at various
luminescent particles were synthesized by the reaction between aqueous yttrium nitrate/europium nitrate salts and ammonium hydroxide solution by bulk precipitation and in the reverse microemulsion composed of NP-5/NP-9, cyclohexane, and water. Compared with luminescent particles formed by the bulk precipitation method, the particles prepared in microemulsion showed a narrower size distribution, spherical shape, smaller size (20-30 nm), higher crystallinity, and stronger photoluminescence. Also,
Amorphous silicon (a-Si) film was crystallized at 500 °C, using a thin Ni layer. The crystallization proceeds by the migration of NiSi2 precipitates through the a-Si network. The crystallization kinetics change with the density of NiSi2 precipitates on the a-Si. The high density of NiSi2 precipitates, formed at a thick Ni layer, leads to vertical migration of the NiSi2 precipitates. With decreasing Ni thickness on a-Si, the spacing between NiSi2 precipitates increases and leads to lateral growth
A new fabrication process for polycrystalline silicon (poly-Si) thin-film transistors (TFTs) on glass substrate is reported. Amorphous silicon (a-Si) was crystallized by metal-induced crystallization (MIC) using a Ni solution for low-temperature crystallization. The a-Si film spin-coated with a 5000 ppm Ni solution was fully crystallized at 500° C. The poly-Si TFT made of the poly-Si exhibited a field-effect mobility of 105 cm 2 /Vs and a threshold voltage of -4 V. The high performance of the po
We present experimental results for laser-induced Au nanoparticle (NP) embedded in a HfO2 high-k dielectric matrix. Cross-sectional transmission electron microscopy images showed that the Au NPs of 8nm in diameter were clearly embedded in HfO2 matrix. Capacitance-voltage measurements of Pt∕HfO2∕AuNPs∕HfO2 on p-type Si substrate reliably exhibited metal-oxide-semiconductor behavior with a large flatband shift of 4.7V. In addition, the charge retention time at room temperature was found to exceed