• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.5
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• pp.321-326
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• 2021

We fabricated BiAlO thin film by a solution process with a brush coating to be used as liquid crystal (LC) alignment layer. Solution-processed BiAlO was coated on the glass substrate by brush process. Prepared thin films were annealed at different temperatures of 80℃, 180℃, and 280℃. To verify whether the BiAlO film was formed properly, X-ray photoelectron spectroscopy analysis was performed on Bi and Al. Using a crystal rotation method by polarized optical microscopy, LC alignment state was evaluated. At the annealing temperature of 280℃, the uniform homogenous LC alignment was achieved. To reveal the mechanism of LC alignment by brush coating, field emission scanning electron microscope was used. Through this analysis, spin-coated and brush coated film surface were compared. It was revealed that physical anisotropy was induced by brush coating at a high annealing temperature. Particles were aligned in one direction along which brush coating was made, resulting in a physical anisotropy that affects a uniform LC alignment. Therefore, it was confirmed that brush coating combined with BiAlO thin film annealed at high temperature has a significant potential for LC alignment.

• Journal of the Semiconductor & Display Technology
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• v.14 no.1
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• pp.61-65
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• 2015

We have fabricated poly(3,4-ethylenedioxythiophene) : poly(4-styrenesulfonate) (PEDOT : PSS) thin films using a slotdie coater for the applications of OLED lightings. It is demonstrated that the properties of slot-die coated PEDOT : PSS films are comparable with those of spin-coated ones. Namely, the average and peak-to-peak roughness of the slot-die coated 50-nm-thick PEDOT : PSS film are measured to be as low as 0.247 nm and 1.3 nm, respectively. Moreover, we have obtained excellent thickness uniformity (~1.91%). With the slot-die coated PEDOT : PSS films, we have fabricated green phosphorescent OLED devices. For comparison, we have also fabricated OLED devices with spin-coated PEDOT : PSS films. Both show almost no discrepancy in device performance. The power efficiency (25.4 lm/W) and emission uniformity (77%) of OLEDs with slot-die coated PEDOT : PSS films are shown to be slightly lower than those (27.3 lm/W, 80%) of OLEDs with spin-coated PEDOT : PSS films at the luminance of 1,000nit, increasing the feasibility of using a slot-die coating process for the fabrication of large-area OLED lighting sources at a competitive price.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.4
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• pp.290-293
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• 2012

This article introduces the characterization of spin coated ZnO transparent conducting oxide on the flexible substrates. As a II-IV compound semiconductor, ZnO has a wide band gap of 3.37 eV with transparent properties. Due to this transparent properties, ZnO materials can be also employed as the transparent conducting electrode materials. Therefore, strong demands have been required for the transparent electrodes with low temperature processing and cheap cost. So, We will investigate the electrical property and optical transmittance of ZnO transparent conducting oxide through the 4-point probe resistivity meter, and ultraviolet-vis spectrometer Lamda 35, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.2
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• pp.128-132
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• 1998

2/65/35 PLZT stock solution prepared by Sol-Gel processing was spin-coated on ITO coated glass and annealed by RTA(Rapid Thermal Annealing). The crystal structure of films was reported based on the observation of crystallization process and microstructure of the film fabricated at different fabrication condition. Films were crystallized into rhombohedral structure by annealing at $750^{\circ}C$ for 5 min. As the annealing temperature increased, the size of rosette structure of the films was grown up from $2.4{\mu}m$ to $15{\mu}m$, dielectric constant was increased, coercive field was decreased 33.82 kV/cm, remnant polarization was increased to 39.84 ${\mu}C/cm^2$ and Optical transmittance was decreased.

• Korean Journal of Materials Research
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• v.33 no.11
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• pp.475-481
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• 2023

Recently, the electron transport layer (ETL) has become one of the key components for high-performance perovskite solar cell (PSC). This study is motivated by the nonreproducible performance of ETL made of spin coated SnO₂ applied to a PSC. We made a comparative study between tin oxide deposited by atomic layer deposition (ALD) or spin coating to be used as an ETL in N-I-P PSC. 15 nm-thick Tin oxide thin films were deposited by ALD using tetrakisdimethylanmiotin (TDMASn) and using reactant ozone at 120 ℃. PSC using ALD SnO₂ as ETL showed a maximum efficiency of 18.97 %, and PSC using spin coated SnO₂ showed a maximum efficiency of 18.46 %. This is because the short circuit current (Jsc) of PSC using the ALD SnO₂ layer was 0.75 mA/cm² higher than that of the spin coated SnO₂. This result can be attributed to the fact that the electron transfer distance from the perovskite is constant due to the thickness uniformity of ALD SnO₂. Therefore ALD SnO₂ is a candidate as a ETL for use in PSC vacuum deposition.

• Journal of the Korean Ceramic Society
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• v.34 no.3
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• pp.314-322
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• 1997

The thin film processing and the applicability as a IMD material of SiO2 aerogels providing ultralow dielec-tric properties were studied. The SiO2 aerogel films with 0.5g/㎤ density (78% porosity) and 4000~21000$\AA$ thickness could be prepared at 25$0^{\circ}C$ and 1160 psig by supercritical drying of wet-gel films, which were spin-coated at the spin rate of 1000~7000 rpm on p-Si(111) wafer under the isopropanol atmosphere. The optimum viscosity of polymeric SiO2 sols for spin coating was in the range of 10~14 cP. The main fac-tors being able to control the film thickness and microstructures were found to be sol concentration, spin rpm, and aging time of wet-gel films. The dielectric constant of the SiO2 aerogel thin film was around 2.0 low enough to be applied to the next generation semiconductor device beyond the giga level.

• Journal of the Korean Vacuum Society
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• v.9 no.1
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• pp.69-75
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• 2000

We have investigated the feasibility of spin on glass (SOG) film from polysilazane-type resin as a premetal dielectric (PMD) layer of the next-generation ultra-large scale integrated (ULSI) devices. A commercial polysilazane resin and a polysilazane-type resin with oxidizing agent were spin-coated and cured to form SOG films. In order to study the effect of oxidizing agent and annealing, the SOG films were characterized as cured and after annealing at $400^{\circ}C$ to $900^{\circ}C$. the density and the resistance against wet chemical of the SOG films were improved by the addition of oxidizing agent, because oxidizing agent enhanced the conversion from polysilazane polymer to $SiO_2$. The hole profile issue associated with insufficient curing of polysilazane in narrow gaps was also resolved by oxidizing agent, while the gapfill capability of SOG was not deteriorated by oxidizing agent.

• Journal of the Korean Ceramic Society
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• v.30 no.9
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• pp.695-700
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• 1993

In this study, we prepared Pb-Ti stock solution by sol-gel processing and deposited PbTiO3 thin film on a Pt coated SiO2/Si wafer by spin coating using the stock solution. We used lead acetate trihydrate and titanium isopropoxide. The stock solution was partially hydrolized and finally a 0.25M coating solution was prepared. We achieved spin coating at 4000rpm for 30 seconds and heated the thin film at 375$^{\circ}C$ for 5 minutes and at $600^{\circ}C$ for 5 minutes successively, first and second heating state. And the thin film was finally sintered at 90$0^{\circ}C$ for 1 hour in the air. The upper electrode of the thin film was made by gold sputtering and was cricle shape with radius 0.4mm. Measured dielectric constant, dissipation factor and phase transition temperature(Cuire Temp.) were about 275, 0.02 and 521$^{\circ}C$ respectively. To observe ferroelectric characteristics we calculated Pr(remnant polarization) and Ec(coercive field) byhysteresis curve. Ec was 72kV/cm and Pr was 11.46$\mu$C/$\textrm{cm}^2$.

• Journal of the Korean Vacuum Society
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• v.13 no.3
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• pp.99-102
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• 2004

In this work the electrical characteristics of organic thin film transistors with the surface-treated organic gate insulator have been studied. For the surface treatment of gate dielectric, Ar plasma was used. Pentacene and PVP were used as active and dielectric layers respectively. Pentacene was thermally evaporated in vacuum at a pressure of about $10^{-6}$ Torr and at a deposition rate of 0.5 $\AA$/sec. PVP was spin coated and cured at $100^{\circ}C$. before pentacene deposition. organic thin film transistors with surface-treated gate insulators have provided improved operation characteristics.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1240_1241
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• 2009

In this paper, sol-gel-spin coated $Pb(ZrTi)O_3$ thin film with $ZrO_2$ buffer-layer and $PbTiO_3$ seed-layer was investigated for vibration MEMS energy harvester to scavenge power from ambient vibration via d33 piezoelectric mode. Piezoelectric thin film deposition techniques on insulating layer is the important key for $d_{33}$ mode of piezoelectric vibration energy harvester. $ZrO_2$ buff-layer was utilized as an insulating layer. $PbTIO_3$ seed-layer was applied as an inter-layer between PZT and $ZrO_2$ layer to improve the crystalline of PZT thin film. The fabricated PZT thin film had a remanent polarization of 5.3uC/$cm^2$ and the coercive field of 60kV/cm. The fabricated energy harvester using PZT thin film with PTO seed-layer generated 1.1uW of electrical power to $2.2M{\Omega}$ of load with $4.4V_{pvp}$ from vibration of 0.39g at 528Hz.