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        검색결과 30

        1.
        2022.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Transparent thin films of pure and nickel-doped ZrO2 are grown successfully by sol-gel dip-coating technique. The structural and optical properties according to the different annealing temperatures (300 oC, 400 oC and 500 oC) are investigated. Analysis of crystallographic properties through X-ray diffraction pattern reveals an increase in crystallite size due to increase in crystallinity with temperature. All fabricated thin films are highly-oriented along (101) planes, which enhances the increase in nickel doping. Scanning electron microscopy and energy dispersive spectroscopy are employed to confirm the homogeneity in surface morphology as well as the doping configuration of films. The extinction coefficient is found to be on the order of 102, showing the surface smoothness of deposited thin films. UV-visible spectroscopy reveals a decrease in the optical band gap with the increase in annealing temperature due to the increase in crystallite size. The variation in Urbach energy and defect density with doping and the change in annealing temperature are also studied.
        4,000원
        2.
        2022.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study demonstrates a different approach method to fabricate antimony selenide (Sb2Se3) thin-films for the solar cell applications. As-deposited Sb2Se3 thin-films are fabricated via electrodeposition route and, subsequently, annealed in the temperature range of 230 ~ 310oC. Cyclic voltammetry is performed to investigate the electrochemical behavior of the Sb and Se ions. The deposition potential of the Sb2Se3 thin films is determined to be -0.6 V vs. Ag/AgCl (in 1 M KCl), where the stoichiometric composition of Sb2Se3 appeared. It is found that the crystal orientations of Sb2Se3 thin-films are largely dependent on the annealing temperature. At an annealing temperature of 250 oC, the Sb2Se3 thin-film grew most along the c-axis [(211) and/or (221)] direction, which resulted in the smooth movement of carriers, thereby increasing the carrier collection probability. Therefore, the solar cell using Sb2Se3 thin-film annealed at 250 oC exhibited significant enhancement in JSC of 10.03 mA/cm2 and a highest conversion efficiency of 0.821 % because of the preferred orientation of the Sb2Se3 thin film.
        4,000원
        3.
        2021.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Cu2ZnSn(S,Se)4 (CZTSSe) based thin-film solar cells have attracted growing attention because of their earthabundant and non-toxic elements. However, because of their large open-circuit voltage (Voc)-deficit, CZTSSe solar cells exhibit poor device performance compared to well-established Cu(In,Ga)(S,Se)2 (CIGS) and CdTe based solar cells. One of the main causes of this large Voc-deficit is poor absorber properties for example, high band tailing properties, defects, secondary phases, carrier recombination, etc. In particular, the fabrication of absorbers using physical methods results in poor surface morphology, such as pin-holes and voids. To overcome this problem and form large and homogeneous CZTSSe grains, CZTSSe based absorber layers are prepared by a sputtering technique with different RTA conditions. The temperature is varied from 510 oC to 540 oC during the rapid thermal annealing (RTA) process. Further, CZTSSe thin films are examined with X-ray diffraction, X-ray fluorescence, Raman spectroscopy, IPCE, Energy dispersive spectroscopy and Scanning electron microscopy techniques. The present work shows that Cu-based secondary phase formation can be suppressed in the CZTSSe absorber layer at an optimum RTA condition.
        4,000원
        5.
        2016.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        To observe the bonding structure and electrical characteristics of a GZO oxide semiconductor, GZO was deposited on ITO glasses and annealed at various temperatures. GZO was found to change from crystal to amorphous with increasing of the annealing temperatures; GZO annealed at 200 oC came to have an amorphous structure that depended on the decrement of the oxygen vacancies; increase the mobility due to the induction of diffusion currents occurred because of an increment of the depletion layer. The increasing of the annealing temperature caused a reduction of the carrier concentration and an increase of the bonding energy and the depletion layer; therefore, the large potential barrier increased the diffusion current dna the Hall mobility. However, annealing temperatures over 200 oC promoted crystallinity by the defects without oxygen vacancies, and then degraded the depletion layer, which became an Ohmic contact without a potential barrier. So the current increased because of the absence of a potential barrier.
        4,000원
        6.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The organic binder-free paste for dye-sensitized solar cell (DSSC) has been investigated using peroxo titanium complex. The crystal structure of TiO2 nanoparticles, morphology of TiO2 film and electrical properties are analyzed by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Electrochemical Impedance Spectra (EIS), and solar simulator. The synthesized TiO2 nanopowders by the peroxo titanium complex at 150, 300, 400˚C, and 450˚C have anatase phase and average crystal sizes are calculated to be 4.2, 13.7, 16.9, and 20.9 nm, respectively. The DSSC prepared by the peroxo titanium complex binder have higher Voc and lower Jsc values than that of the organic binder. It can be attributed to improvement of sintering properties of TCO/TiO2 and TiO2/TiO2 interface and to formation of agglomerate by the nanoparticles. As a result, we have investigated the organic binder-free paste and 3.178% conversion efficiency of the DSSC at 450˚C.
        4,000원
        7.
        2012.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        For heat exchanger applications, 2-ply clad materials were fabricated by rolling of aluminum (Al) and mild steel sheets. Effects of annealing temperature on interface properties, especially on inter-layer formation and softening of strain hardened mild-steel, for Al/mild steel clad materials, were investigated. To obtain optimum annealing conditions for the Al/mild steel clad materials, annealing temperature was varied from room temperature to 600˚C. At the annealing temperature about 450˚C, an inter-layer was formed in an island-shape at the interface of the Al/mild steel clad materials; this island expanded along the interface at higher temperature. By analyzing the X-ray diffraction (XRD) peaks and the energy dispersive X-ray spectroscopy (EDX) results, it was determined that the exact chemical stoichiometry for the inter-layer was that of Fe2Al5. In some samples, an X-layer was formed between the Al and the inter-layer of Fe2Al5 at high annealing temperature of around 550˚C. The existence of an X-layer enhanced the growth of the inter-layer, which resulted in the delamination of the Al/mild-steel clad materials. Hardness tests were also performed to examine the influence of the annealing temperature on the cold deformability, which is a very important property for the deep drawing process of clad materials. The hardness value of mild steel gradually decreased with increasing annealing temperature. Especially, the value of hardness sharply decreased in the temperature range between 525˚C and 550˚C. From these results, we can conclude that the optimum annealing temperature is around 550˚C under condition of there being no X-layer creation.
        4,000원
        8.
        2010.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Twinning-induced plasticity (TWIP) steels have attracted great attention due to their excellent mechanical properties of high tensile strength (over 800MPa) and high ductility (over 50%), which result from the high strain hardening due to the mechanical twin formation during plastic deformation. The purpose of this study is to investigate the effect of annealing temperature and alloying elements on the mechanical properties of Fe-18Mn-0.6C TWIP steel. In 1.5%Al TWIP steel with 0.123%Ti content, the average recrystallized grain size was reduced to 2.5 μm by cold rolling and annealing at 800˚C for 5 min, because of the pinning effect of the fine TiC carbides on grain coarsening. The tensile strength was decreased and the ductility was improved with the increase of the annealing temperature. However, a reversion of hardness and yield strength happened between 750˚C and 800˚C due to TiC and M3C type precipitation. 0.56% Ni added TWIP steel exhibited relatively lower yield strength, because Ni precipitates were not formed during the annealing process. When this specimen was annealed at 800˚C for 5min, the tensile strength and elongation were revealed at 1096MPa and 61.8%, respectively.
        4,000원
        9.
        2009.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Polymer Light Emitting Diodes (PLEDs) with an ITO/PEDOT:PSS/PVK/PFO-poss/LiF/Al structure were prepared on plasma-treated ITO/glass substrates using spin-coating and thermal evaporation methods. The annealing effects of the PFO-poss film when it acts as the emission layer were investigated by using electrical and optical property measurements. The annealing conditions of the PFO-poss emission film were 100 and 200˚C for 1, 2 and 3 hours, respectively. The luminance increased and the turn-on voltage decreased when the annealing temperature and treatment time increased. After examining the Luminance-Voltage (L-V) properties of the PLED, the maximum luminance was found to be 1497 cd/m2 at 11 V for the device when it was annealed at 200˚C for 3 hours. The peak intensity of the PLED emission spectra at approximately 525 nm in wavelength increased when the annealing temperature and time of the PFO-poss film increased. These results suggest that the light emission color shifted from blue to green.
        4,000원
        10.
        2009.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Transparent Sn-doped In2O3 (ITO) single-layer and ITO/Au/ITO multilayer films were deposited onglass substrates by reactive magnetron sputtering to compare the properties of the films. They were thenannealed in a vacuum of 1×10-2 Pa at temperatures ranging from 150 to 450oC for 20 min to determinethe effect of the annealing temperature on the properties of the films. As-deposited 100nm thick ITO filmsexhibit a sheet resistance of 130Ω/□ and optical transmittance of 77% at a wavelength length of 550nm. Byinserting a 5nm-thick Au layer in ITO/metal/ITO (IMI) films, the sheet resistance was decreased to as lowas 20Ω/□ and the optical transmittance was decreased to as little as 73% at 550nm. Post-deposition annealingof ITO/Au/ITO films led to considerably lower electrical resistivity and higher optical transparency. In the X-ray diffraction pattern, as-deposited ITO films did not show any diffraction peak, whereas as-deposited ITO/Au/ITO films have Au (222) and In2O3 (110) crystal planes. When the annealing temperature reached the 150- 450oC range, the both diffraction peak intensities increased significantly. A sheet resistance of 8Ω/□ and anoptical transmittance of 82% were obtained from the ITO/Au/ITO films annealed at 450oC.
        3,000원
        11.
        2008.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Modified thermal annealing was applied to the activation of the polycrystalline silicon films doped as p-type through implantation of B2H6. The statistical design of experiments was successfully employed to investigate the effect of rapid thermal annealing on activation of polycrystalline Si doped as p-type. In this design, the input variables are furnace temperature, power of halogen lamps, and alternating magnetic field. The degree of ion activation was evaluated as a function of processing variables, using Hall effect measurements and Raman spectroscopy. The main effects were estimated to be furnace temperature and RTA power in increasing conductivity, explained by recrystallization of doped ions and change of an amorphous Si into a crystalline Si lattice. The ion activation using rapid thermal annealing is proven to be a highly efficient process in low temperature polycrystalline Si technology.
        4,000원
        12.
        2008.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The effect of silver nanoparticles (NPs) incorporation on the electronic properties of poly (3, 4-ethylenedioxythiphene) : poly(styrenesulfonate) (PEDOT : PSS) films was investigated. The surface of silver NPs was stabilized with trisodium citrate to control the size of silver NPs and prevent their aggregation. We obtained ca. 5 nm sized silver NPs and dispersed NPs in PEDOT : PSS solution. Sheet resistance, surface morphology, bonding state, and work function values of the PEDOT : PSS films were modified by silver NPs incorporation as well as annealing temperature. Sodium in silver NPs solution could lead to a decrease of work function of PEDOT : PSS; however, large content of silver NPs have an effect on the increase in work function, resulting from charge localization on the silver NPs and a decrease in the number of charge-trapping-related defects by chemical bond formation.
        3,000원
        13.
        2008.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, BaTiO3 thin films were grown by RF-magnetron sputtering, and the effects of a post-annealing process on the structural characteristics of the BaTiO3 thin films were investigated. For the crystallization of the grown thin films, post-annealing was carried out in air at an annealing temperature that varied from 500-1000˚C. XRD results showed that the highest crystal quality was obtained from the samples annealed at 600-700˚C. From the SEM analysis, no crystal grains were observed after annealing at temperatures ranging from 500 to 600˚C; and 80 nm grains were obtained at 700˚C. The surface roughness of the BaTiO3 thin films from AFM measurements and the crystal quality from Raman analysis also showed that the optimum annealing temperature was 700˚C. XPS results demonstrated that the binding energy of each element of the thin-film-type BaTiO3 in this study shifted with the annealing temperature. Additionally, a Ti-rich phenomenon was observed for samples annealed at 1000˚C. Depth-profiling analysis through a GDS (glow discharge spectrometer) showed that a stoichiometric composition could be obtained when the annealing temperature was in the range of 500 to 700˚C. All of the results obtained in this study clearly demonstrate that an annealing temperature of 700˚C results in optimal structural properties of BaTiO3 thin films in terms of their crystal quality, surface roughness, and composition.
        4,000원
        14.
        2008.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Fe-aluminides have the potential to replace many types of stainless steels that are currently used in structural applications. Once commercialized, it is expected that they will be twice as strong as stainless steels with higher corrosion resistance at high temperatures, while their average production cost will be approximately 10% of that of stainless steels. Self-propagating, high-temperature Synthesis (SHS) has been used to produce intermetallic and ceramic compounds from reactions between elemental constituents. The driving force for the SHS is the high thermodynamic stability during the formation of the intermetallic compound. Therefore, the advantages of the SHS method include a higher purity of the products, low energy requirements and the relative simplicity of the process. In this work, a Fe-aluminide intermetallic compound was formed from high-purity elemental Fe and Al foils via a SHS reaction in a hot press. The formation of iron aluminides at the interface between the Fe and Al foil was observed to be controlled by the temperature, pressure and heating rate. Particularly, the heating rate plays the most important role in the formation of the intermetallic compound during the SHS reaction. According to a DSC analysis, a SHS reaction appeared at two different temperatures below and above the metaling point of Al. It was also observed that the SHS reaction temperatures increased as the heating rate increased. A fully dense, well-bonded intermetallic composite sheet with a thickness of 700 μm was formed by a heat treatment at 665˚C for 15 hours after a SHS reaction of alternatively layered 10 Fe and 9 Al foils. The phases and microstructures of the intermetallic composite sheets were confirmed by EPMA and XRD analyses.
        4,000원
        15.
        2008.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The effects of the deposition and annealing temperature on the structural, electrical and opticalproperties of Ag doped ZnO (ZnO:Ag) thin films were investigated. All of the films were deposited with a 2wt%Ag2O-doped ZnO target using an e-beam evaporator. The substrate temperature varied from room temperature(RT) to 250oC. An undoped ZnO thin film was also fabricated at 150oC as a reference. The as-grown films wereannealed in temperatures ranging from 350 to 650oC for 5h in air. The Ag content in the film decreased asthe deposition and the post-annealing temperature increased due to the evaporation of the Ag in the film.During the annealing process, grain growth occurred, as confirmed from XRD and SEM results. The as-grownfilm deposited at RT showed n-type conduction; however, the films deposited at higher temperatures showedp-type conduction. The films fabricated at 150oC revealed the highest hole concentration of 3.98×1019cm-3 anda resistivity of 0.347Ω·cm. The RT PL spectra of the as-grown ZnO:Ag films exhibited very weak emissionintensity compared to undoped ZnO; moreover, the emission intensities became stronger as the annealingtemperature increased with two main emission bands of near band-edge UV and defect-related greenluminescence exhibited. The film deposited at 150oC and annealed at 350oC exhibited the lowest value of Ivis/Iuv of 0.05.
        4,000원
        16.
        2008.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The electromagnetic (EM) wave absorption properties with a variation of crystallization annealing temperature have been investigated in a sheet-type absorber using the alloy powder. With increasing the annealing temperature the complex permeability (), permittivity () and power absorption changed. The EM wave absorber shows the maximum permeability and permittivity after the annealing at for 1 hour, and its calculated power absorption is above 80% of input power in the frequency range over 1.5 GHz.
        4,000원
        18.
        2006.09 구독 인증기관·개인회원 무료
        Magnetic Properties of dust cores made of mixtures of atomized pure iron powder and pure alumina powder has been investigated in the temperature range from 673 to 1073K. The effect of annealing on coercivity has been positive effect up to 973K and thus coercivity is gradually reduced form 280A/m (as-compressed) to 160A/m (973K). However, dust cores annealed at 1073K displayed a 15% increasing of coercivity by annealing at 973K. Hysteresis loss shows a tendency similar to coercivity. Microstructure observation of specimens shows grain refinement by recrystallization in the temperature range from 773 to 1073K.
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