• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.1030-1035
• /
• 2001

Strontium barium niobate, (Sr$\sub$0.5/Ba$\sub$0.5/Nb$_2$O$\sub$6/), thin films of various composition were prepared by the sol-gel method. Solution derived from acetate powders and niobium ethoxide in a mixture of acetic acid, ethylene glycol and 2-methoxyehanol was spin-coated onto bare silicon, Pt-coated silicon and fused silica substrates. Processing parameters were optimized to develop stable solutions which yielded films with relatively low crystallization temperatures. It was determined that ethylene glycol was a necessary component of the solution to increase stability against precipitation and to decrease the crystallization temperature of the films as confirmed by XRD and FT-IR analyses.

• Korean Journal of Materials Research
• /
• v.27 no.11
• /
• pp.577-582
• /
• 2017

Self-cleaning and photocatalytic $TiO_2$ thin films were prepared by a facile sol-gel method followed by spin coating using peroxo titanic acid as a precursor. The as-prepared thin films were heated at low temperature($110^{\circ}C$) and high temperature ($400^{\circ}C$). Thin films were characterized by X-ray diffraction(XRD), Field-emission scanning electron microscopy(FESEM), UV-Visible spectroscopy and water contact angle measurement. XRD analysis confirms the low crystallinity of thin films prepared at low temperature, while crystalline anatase phase was found the for high temperature thin film. The photocatalytic activity of thin films was studied by the photocatalytic degradation of methylene blue dye solution. Self-cleaning and photocatalytic performance of both low and high temperature thin films were compared.

• Transactions on Electrical and Electronic Materials
• /
• v.11 no.5
• /
• pp.212-215
• /
• 2010

$BiFeO_3/Pb(Zr_{0.95}Ti_{0.05})O_3$ (BFO/PZT) heterolayered thin films were fabricated by the spin coating method on a Pt/Ti/$SiO_2$/Si substrate using metal alkoxide solutions. The coating and heating procedure was repeated 6 times to form the heterolayered films. The thickness of the BFO/PZT films after one cycle of drying/sintering is about 30-40 nm. All BFO/PZT films show a void free uniform grain structure without the presence of rosette structures. It can be assumed that the crystal growth of the upper BFO layers can be influenced by the lower PZT layers. As the number of coatings increased, the dielectric constant increased, so that the value for the 6-layer film was 1360 at 1 KHz.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.11C no.2
• /
• pp.18-22
• /
• 2001

The thin films of high permitivity in ferroelectric materials using a capacitor are applied to DRAMs and FRAMs. (Ba, Sr)TiO$_3$ thin as ferroelectric materials were prepared by the sol-gel method and made by spin-coating on the Pt/Sio$_2$/Si substrate at 4,000 [rpm] for 10 seconds. The structural characteristics of the surface were analyzed by fractal dimension. The thickness of BST ceramics thin films was about 260∼280 [nm]. The property of the leakage current was stable with 10-9∼10-11[A] when the applied voltage was 0∼3[V]. BST thin films ha low leakage current properties when fractal dimension was low and a coating area was high.

• Applied Chemistry for Engineering
• /
• v.16 no.2
• /
• pp.187-193
• /
• 2005

The photocatalyst $TiO_2$ thin film was made from titanium (IV) isopropoxide, ethanol, and HCl by sol-gel method. The surface observation by SEM showed the sample that was coated 5 times at $500^{\circ}C$ had good properties. The component ratio, in atom% of O : Ti by EDX analysis, of 61 : 39 by spin coating was superior than dip coating. It was found that crystal structure changed from anatase phase to rutile phase as a function of the temperature of thin film fabrication, and this was measured by XRD. The photolysis efficiency of total organic compounds (TOC) by lighting UV beam on $TiO_2$ thin film showed 20%~65% within 1 h, and decreased slowly thereafter.

• Korean Chemical Engineering Research
• /
• v.53 no.3
• /
• pp.350-356
• /
• 2015

The effects of the zinc oxide (ZnO) preparing process on the performance of inverted organic photovoltaic cells (OPVs) were explored. The morphology and size of ZnO nanoparticles were controlled, leading to more efficient charge collection from device and higher electron mobility compared with nanospheres. Nanosized ZnO particles were synthesized by using zinc acetate dihydrate and potassium hydroxide in methanol. Also, water was added into the reaction medium to control the morphology of ZnO nanocrystals from spherical particles to rods, and $NH_4OH$ was used to prevent the gelation of dispersion. Solution-processed ZnO thin films were deposited onto the ITO/glass substrate by using spin coating process and then ZnO films were used as an electron transport layer in inverted organic photovoltaic cells. The analyses were carried out by using TEM, FE-SEM, AFM, DLS, UV-Vis spectroscopy, current density-voltage characteristics and solar simulator.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07b
• /
• pp.809-812
• /
• 2004

(Pb,Sr)TiO3 (PST) thin films were fabricated by using the alkoxide-based sol-gel method. The PST stock solution was made and then spin-coated onto a PUTi/SiO2/Si substrate. The coating and drying procedures were repeated several times, and the PST thin films were sintered at 450-650 C for 1 h. All PST thin films showed dense and homogeneous structures without the presence of any rosette structure. The thicknesses of the PST thin films were approximately 200 nm. The dielectric constant and the dielectric loss of the PST thin films sintered at 550 C were about 404 and 0.0023, respectively. The leakage current density of the PST thin film sintered at 550 C was 3.13 x 10-8 A/cm2 at 1 V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.05c
• /
• pp.93-96
• /
• 2002

In this study, PZT thin films were fabricated using sol-gel processing onto Si/$SiO_2$/Ti/Pt substrates. PZT sol with different Zr/Ti ratio(20/80, 30/70, 40/60, 52/48) were prepared, respectively. The films were fabricated by using the spin-coating method on substrates. The films were heat treated at $450^{\circ}C$, $650^{\circ}C$ by rapid thermal annealing(RTA). The preferred orientation of the PZT thin films were observed by X-ray diffraction(XRD), and Scanning electron microscopy(SEM). All of the resulting PZT thin films were crystallized with perovskite phase. The fine crystallinity of the films were fabricated. Also, we found that the ferroelectric properties from the dielectric constant of the PZT thin films were over 600 degrees, P-E hysteresis constant. And the leakage current densities of films were lower than $10^{-8}A/cm^2$. It is concluded that the PZT thin films by sol-gel process to be convinced of application for ferroelectric memory device.

• Electrical & Electronic Materials
• /
• v.8 no.5
• /
• pp.606-610
• /
• 1995

In this study, Pb(Z $r_{0.52}$ $Ti_{0.48}$) $O_{3}$ ceramic thin films were fabricated from an alkoxide-based by Sol-Gel method. Pb(Z $r_{0.52}$ $Ti_{0.48}$) $O_{3}$ stock solution was made and spin-coated on the Pt/ $SiO_{2}$/Si substrate at 4000[rpm] for 30[sec.]. Coated specimens were chied at 400[.deg. C] for 10[min]. The coating process was repeated 6 times and then heat-treated at 500-800[.deg. C] and 1 hour. The final thickness of the thin films were about 4800[.angs.]. The ferroelectric perovskite phases precipitated under the sintering of 700[.deg. C] for 1 hour. Pb(Z $r_{0.52}$ $Ti_{0.48}$) $O_{3}$ thin films sintered at 700[.deg. C] for 1 hour showed good dielectric and ferroelectric properties.

• Bulletin of the Korean Chemical Society
• /
• v.23 no.12
• /
• pp.1724-1728
• /
• 2002

The adsorption of proteins on the surface of glass slides is essential for the construction of protein chips. Here, we report that a Histidine (His)-tagged protein protein has been efficiently adsorbed on glass coated with nickel. A variety of nickel chloride-coated plates were prepared by the spin-coating method and adsorbed to the His-tagged protein. When the protein was adsorbed onto the surface of a variety of nickel chloride-coated glass slides, the efficiency of protein adsorption was dependent upon the coating conditions such as nickel chloride concentration, the spin speed and the drying temperature. The slides appropriate for protein adsorption were obtained when the slides were coated with 11%(w/w) of $NiCl_2$ at the spin speed of 4000 rpm for 20 sec and then dried at higher than 40°C. The physical properties of their nickel chloride thin layer were characterized by scanning electron microscopy. x-ray diffraction and atomic force microscopy, finding that the nickel chloride particles were around 10 nm in diameter and uniformly crystallized at 101 faces. These results show that nickel chloride-coated slides prepared by the spin-coating method are utilizable for the construction of Histagged protein chips.