Hanyang University · Engineering
Professor Ji-Hoon Ahn's research lab specializes in the development and fundamental characterization of advanced 2D and oxide thin films for next-generation electronic and optoelectronic applications. The lab focuses on atomic layer deposition (ALD)-based synthesis of high-quality, wafer-scale 2D materials such as MoS₂ and SnS₂, as well as ferroelectric and dielectric HfO₂-based oxides for memory and sensor devices. Key research directions include controlled polymorphic growth of 2D semiconductors, surface-sensitive gas sensing using vertically aligned 2D nanostructures, and the engineering of dielectric properties in complex oxide thin films through doping and interfacial engineering. The lab combines advanced thin-film deposition techniques with in-depth materials characterization to enable scalable, high-performance nanomaterials for industrial integration.
Figures are computed from collected data and may differ slightly.
van der Waals layered materials have large crystal anisotropy and crystallize spontaneously into two-dimensional (2D) morphologies. Two-dimensional materials with hexagonal lattices are emerging 2D confined electronic systems at the limit of one or three atom thickness. Often these 2D lattices also form orthorhombic symmetries, but these materials have not been extensively investigated, mainly due to thermodynamic instability during crystal growth. Here, we show controlled polymorphic growth of
2D layered materials with sensitive surfaces are promising materials for use in chemical sensing devices, owing to their extremely large surface-to-volume ratios. However, most chemical sensors based on 2D materials are used in the form of laterally defined active channels, in which the active area is limited to the actual device dimensions. Therefore, a novel approach for fabricating self-formed active-channel devices is proposed based on 2D semiconductor materials with very large surface areas
The dielectric properties of the Si-doped Zr1-xHfxO2 thin films were investigated over a broad compositional range with the goal of improving their properties for use as DRAM capacitor materials. The Si-doped Zr1-xHfxO2 thin films were deposited on TiN bottom electrodes by atomic layer deposition using a TEMA-Zr/TEMA-Hf mixture precursor for deposition of Zr1-xHfxO2 film and Tris-EMASiH as a Si precursor. The Si stabilizer increased the tetragonality and the dielectric constant; however, at high
Monolayer transition metal dichalcogenide compounds with two-dimensional (2D) layered structures may be used as next-generation active materials for electronic and optoelectronic devices. A reliable method for creating high-quality, wafer-scale material with well-controlled large-area growth is required for industrial applications. Two-dimensional material atomic layer deposition (ALD) can be used as an atomically flat monolayer film, but its deposition characteristics limit perfect monolayer fo
HfO2-based ferroelectric thin films deposited via atomic layer deposition have been extensively studied as promising candidates for next-generation ferroelectric devices. The conversion of an amorphous Hf1-xZrxO2 film to the ferroelectric phase (non-centrosymmetric orthorhombic phase) has been achieved through annealing using a post-thermal process. However, in this study, we present the first report of ferroelectricity of hafnium-zirconium-oxide (HZO) thin films deposited via atomic layer depos
Sr Ti O 3 thin films were deposited on Ru using plasma-enhanced atomic layer deposition with and without a SrO interlayer. When the SrTiO3 films were deposited on Ru directly, the dielectric constants of the films decreased abruptly from 65 to 16 as the thickness fell below 20nm. This change was related to film crystallinity. Conversely, when a seed layer was prepared by depositing 2.7nm SrO and postannealing before SrTiO3 deposition, the crystallinity of the SrTiO3 films was enhanced and the th
Abstract Fluorite‐structure ferroelectric thin films have been extensively studied as promising candidates for next‐generation non‐volatile memory. However, these ferroelectric thin films have fatal issues such as the irregular formation of the ferroelectric phase, low cycling endurance, and wake‐up and fatigue during endurance cycling tests. These problems are reportedly caused by oxygen vacancies, which form due to the interface reaction between the thin films and bottom electrodes during depo
Abstract Facile synthesis of 3D structured materials with highly slippery and stretchable properties is proposed by infusing lubricant into the wrinkled structures formed on the surface of silicone elastomer in a programmable manner. Such a method allows the formation of slippery surface with the desired 3D hierarchical structures for target applications. The developed platform shows 8.2 times lower ice adhesion strengths or 1.4 times higher water collection properties than planar slippery surfa
Abstract 2D semiconductor materials with layered crystal structures have attracted great interest as promising candidates for electronic, optoelectronic, and sensor applications due to their unique and superior characteristics. However, a large‐area synthesis process for various applications and practical mass production is still lacking. In particular, there is a limitation in that a high process temperature and a very long process time are required to deposit a crystallized 2D material on a la
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