Donghun Kim

SrTi${}_{1\ensuremath{-}x}$M${}_{x}$O${}_{3}$ films in which M = Fe, Co, or Cr and $x=0.04$--0.5 have been grown epitaxially on CeO${}_{2}$-buffered Si, SrTiO${}_{3}$, and LaAlO${}_{3}$ substrates. Films grown in vacuum containing Fe or Co typically showed a strong uniaxial magnetic anisotropy in the out-of-plane direction, a saturation moment on the order of 0.5\ensuremath{\mu}${}_{\mathrm{B}}$/Fe or Co, and a magnetization that persists to temperatures of order 1000 K. In contrast, films conta

We investigated the indium doping effects on ZnO thin film using radio frequency (rf) magnetron sputtering and rapid thermal annealing. The structural and electrical properties of indium doped ZnO thin films were measured by X-ray diffraction, atomic force microscopy, scanning electron microscopy, and Hall effect measurement. Thin films were deposited at a high temperature of in order to improve the crystal quality and were annealed for a short time of only , sufficient time to activate the dopa

The authors report on the dielectric and leakage current properties of room temperature grown MgO-Ba0.6Sr0.4TiO3 (MgO-BST) composite thin films to be utilized InGaZnO4 thin films transistors (TFTs) fabricated on a polyethylene terephthalate (PET) substrate. The InGaZnO4 TFTs with MgO-BST gate dielectrics exhibited low operation voltage of 4V, high on/off current ratio of 4.13×106, and high field effect mobility of 10.86cm2∕Vs. These results verify that a room temperature grown MgO-BST gate diele

Combinatorial pulsed laser deposition (CPLD) using two targets was used to produce a range of transition metal-substituted perovskite-structured Sr(Ti(1-x)M(x))O(3-δ) films on buffered silicon substrates, where M = Fe, Cr, Ni and Mn and x = 0.05-0.5. CPLD produced samples whose composition vs distance fitted a linear combination of the compositions of the two targets. Sr(Ti(1-x)Fe(x))O(3-δ) films produced from a pair of perovskite targets (SrTiO(3) and SrFeO(3) or SrTiO(3) and SrTi0(0.575)Fe(0.4

The effect of loading on chloride penetration into concrete is evaluated in this study. It is found that the chloride penetration rates for OPC concrete and blast furnace slag BFS concrete under the tensile stress were increased by 29% and 77%, respectively. The diffusion coefficient of BFS concrete was lower than that of conventional concrete without BFS, no loads and stress states. Under tensile stress, the diffusion coefficient for BFS and plain concrete showed higher values with increasing s

We report on the fabrication and characterization of sputter-deposited poly(methyl methacrylate) (PMMA) thin films used as gate insulators as well as passivation layers in high performance thin-film transistors (TFTs). Sputter-deposited PMMA thin films exhibited a dielectric constant of 4.3 and low leakage current characteristics ( at 0.3 MV/cm). The TFTs utilizing PMMA gate insulators and PMMA passivation layers exhibited a high on/off current ratio of and a high field-effect mobility of . Thre

Strain-induced modulation of electronic, magnetic, and photonic properties provides additional functionalities to oxide thin film-based electronics as compared to those of conventional rigid electronics. Herein, we introduce a simple transfer process for highly crystalline nanometer-thick films onto flexible polydimethylsiloxane (PDMS) using water-soluble sacrificial NaCl crystals. The c axis of the high-temperature sputtered ZnO thin films grew along a parallel direction to the substrate surfac

We investigated the thickness dependence of a room-temperature grown composite gate dielectric and an active semiconductor on the electrical characteristics of thin-film transistors (TFTs) fabricated on a polyethylene terephthalate substrate. The optimum gate dielectric and active semiconductor thickness were 300 and , respectively. The TFT showed a high field-effect mobility of , an on/off ratio of , a threshold voltage of , and a subthreshold swing of .

We investigated indium- (In)-doping effects on the structural and electrical properties of a ZnO film. It was found that structural properties degraded as In-doping content increased, whereas electrical properties improved. We fabricated fully transparent and flexible thin film transistors (TFTs) using In-doped ZnO electrodes on polyethylene terephthalate (PET) substrate. The In-doped ZnO∕PET stacks exhibited a high transmittance of 80% in the visible range. The TFT with a 3% In-doped ZnO electr