• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.12
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• pp.1072-1076
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• 2007

We prepared the Al doped ZnO (AZO) thin film on polyethersulfon (PES) without any substrate heating by Facing Targets Sputtering (FTS) system. FTS system has two different facing targets. One is ZnO doped the content of Al 2 wt% and the other is Zn in order to decrease resistivity. The electrical, structural and optical properties of AZO thin films were investigated. To evaluate the as-deposited thin film properties, we employed four-point probe (CMT-R100nw, Changmin), Surface profiler (Alpha-step, Tencor), UV/VIS spectrometer (HP), X-ray diffractometer (XRD, Rigaku) and Field Emission Scanning Electron Microscopy (FESEM, Hitachi S-4700). As a result, We obtained that AZO thin film deposited on PES substrate at a DC Power of 150 W, working pressure of 1 mTorr and $O_2$ gas flow ratio of 0.2 exhibited the resistivity of $4.2{\times}10^{-4}\;[{\Omega}cm]$ and the optical transmittance of about 85 % in the visible range.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.215-219
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• 2004

Metal-chelate derivatives have been investigated intensively as an emitting layer and recognize to have excellent electroluminescence(EL) properties. We synthesized new luminescent material, 1,4-dihydoxy-5,8-naphtaquinone $Aiq_3$ complex($Al_2Nq_4$) and investigated the electrical optical properties. OLED has potential candidates for information display with merits of thickness, low power and high efficiency. Although the OLED show a lot of advantages for information display, it has the limit of inorganic(metal)/ organic interface. In this study, the two methods are used to study the interface of metal/organic in OLED. First, we treated $O_2$ plasma on an ITO thin film by using RIE system, and analyzed the ingredient of ITO thin film according to change of the processing conditions. We used the RDS and the XPS for the ingredient analysis of the surface and bulk. We measured electrical resistivity using Four-Point-Probe and calculated sheet resistance, and ITO surface roughness was measured by using AFM. We fabricated OLED using substrate that was treated optimum ITO surface. Second, we used the buffer layer of CuPc to improve the characteristics of the interface and the hole injection in OLED. The result of the study for electrical and optical properties by using I V L T System(Flat Panel Display Analysis System), we confirmed that the electrical properties and the luminance properties were improved.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.1
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• pp.49-55
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• 2023

The deposition of indium zinc oxide (IZO) thin films was carried out on substrate at room temperature by RF magnetron sputtering. The effects of substrate temperature, RF power and deposition pressure were investigated with respect to physical and optical properties of films such as deposition rate, electrical properties, structure, and transmittance. As the RF power increases, the resistivity gradually decreases, and the transmittance slightly decreases. For the variation of deposition pressure, the resistivity greatly increases, and the transmittance is decreased with increasing deposition pressure. As a result, it was demonstrated that an IZO film with the resistivity of 3.89 × 10^-4 Ω∙cm, the hole mobility of 51.28 cm²/Vs, and the light transmittance of 86.89% in the visible spectrum at room temperature can be prepared without post-deposition annealing.

• Korean Journal of Materials Research
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• v.20 no.9
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• pp.494-499
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• 2010

Tin oxide thin films were prepared on borosilicate glass by rf reactive sputtering at different deposition powers, process pressures and substrate temperatures. The ratio of oxygen/argon gas flow was fixed as 10 sccm / 60 sccm in this study. The structural, electrical and optical properties were examined by the design of experiment to evaluate the optimized processing conditions. The Taguchi method was used in this study. The films were characterized by X-ray diffraction, UV-Vis spectrometer, Hall effect measurements and atomic force microscope. Tin oxide thin films exhibited three types of crystal structures, namely, amorphous, SnO and $SnO_2$. In the case of amorphous thin films the optical band gap was widely spread from 2.30 to 3.36 eV and showed n-type conductivity. While the SnO thin films had an optical band gap of 2.24-2.49 eV and revealed p-type conductivity, the $SnO_2$ thin films showed an optical band gap of 3.33-3.63 eV and n-type conductivity. Among the three process parameters, the plasma power had the most impact on changing the structural, electrical and optical properties of the tin oxide thin films. It was also found that the grain size of the tin oxide thin films was dependent on the substrate temperature. However, the substrate temperature has very little effect on electrical and optical properties.

• Transactions on Electrical and Electronic Materials
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• v.9 no.1
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• pp.28-32
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• 2008

Hydrogenated microcrystalline silicon(${\mu}c$-Si:H) films were prepared using inductively coupled plasma chemical vapor deposition(ICP-CVD) method, electrical and optical properties of these films were studied as a function of silane concentration. And then, effect of $PH_3\;and\;B_2H_6$ addition on their electrical properties was also investigated for solar cell application. Characterization of these films from X-ray diffraction revealed that the conductive film exists in microcrystalline phase embedded in an amorphous network. At $PH_3/SiH_4$ gas ratio of $0.9{\times}10^{-3}$, dark conductivity has a maximum value of ${\sim}18.5S/cm$ and optical bandgap also a maximum value of ${\sim}2.39eV$. Boron-doped ${\mu}c$-Si:H films, satisfied with p-layer of solar cell, could be obtained at ${\sim}10^{-2}\;of\;B_2H_6/SiH_4$.

• Electrical & Electronic Materials
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• v.8 no.4
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• pp.458-463
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• 1995

The optical and electrical properties of $C_{22}$-Quinolinium(TCNQ) Langmuir-Blodgett films have been studied depending on the annealing temperatures. The optimal properties were investigated using UV/visible(300-800[nm]) absorption spectra and FTIR(Fourier-transformed- infrared) absorption measurements. The electrical properties were investigated in a frequency range of 10[Hz]-13[MHz]. The UV/visible absorption spectra at room temperature show that there are four characteristic peaks at 320, 380, 494 and 678[nm]. These absorption peaks decrease very rapidly above the annealing temperature of 180[.deg. C], which is due to a structural change of TCNQ. The FTIR absorption measurements strongly support the result of the UV/visible absorption spectra, because the absorption peak of TCNQ- at 2181[$cm^{-1}$ /] also decreases above 140[.deg. C]. The frequency-dependent dielectric constant shows that there is a dielectric dispersion near 1[MHz] which is due to an orientational polarization of the molecules inside the film. The overall frequency-dependent dielectric constant is higher near 80[.deg. C]. It may be due to a softness of the alkyl chains.s.

• Korean Journal of Crystallography
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• v.8 no.2
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• pp.105-110
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• 1997

1μm-CdS films for a window layer of CdS/CuInSe2 solar cell have been prepared by vacuum of 1x10-3 mTorr. Source and substrate temperature ranges were used 800-1100'C and 50-200℃ respectively. Structural, electircal and optical properties of CdS films have been investigated by X-ray diffractometer (XRD), scanning electron microscopy (SSEM), electrical resistivity, the Hall measurement and optical transmission spectra. Electrical resistivity and optical transmission of the CdS films decreased with the increase in CdS source temperature without substrate heating. All the films had hexagonal structure and strong texture with (002) orientation of grain normal to the substrate glass. CdS films evaporated at 1000℃ were the highest electrical conductivity of 0.9(S/cm). Electrical resistivity and optical transmission at the substrate temperature of 100℃ were 40(Ω,cm) and 80% respectively.

• Korean Journal of Materials Research
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• v.18 no.8
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• pp.422-426
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• 2008

The effects of an addition of $ZrO_2$ on the microstructure and electrical properties of MgO films as a protective layer for AC plasma display panels were investigated. MgO + a 200 ppm $ZrO_2$ protective layer prepared by e-beam evaporation exhibited a secondary electron emission coefficient ($\gamma$) that was improved by 21% compared to that of a pure MgO protective layer. The relative density and Vickers hardness increased with a further addition of $ZrO_2$. These results suggest that the discharge properties and optical properties of MgO protective layers are closely related to the relative density and Vickers hardness. The good optical and electrical properties of $\gamma$, at 0.080, a grain size of $19\;{\mu}m$ and an optical transmittance of 91.93 % were obtained for the MgO + 200 ppm $ZrO_2$ protective layer sintered at $1700^{\circ}C$ for 5 hrs.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.4
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• pp.322-327
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• 2006

CdS films have been prepared on polycarbonate, polyethylene terephthalate, and Coming 7059 substrates by r.f magnetron sputtering technique at room temperature. A comparison of the properties of the films deposited on polymer and glass substrates was performed. In addition, the influence of the sputter power on the structural and optical properties of these films was evaluated. The XRD measurements revealed that CdS films were polycrystalline and retained the mixed structure of hexagonal wurtzite and cubic phase, regardless of substrate types. As the sputter power was increased from 75 to 150 Watt, the structure of CdS films was converted from the mixed of hexagonal and cubic phase to hexagonal phase. The morphology of CdS films is found to be continuous and dense. Also, the grain of CdS films is larger with increasing the sputter power. The average transmittance exceeded 80 % in the visible spectrum for all films and decreases slightly with the sputter power.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.125-126
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• 2006

ZnO Films have been prepared on polycarbonate (PC), polyethylene terephthalate (PET), and Coming 7059 substrates by r.f. magnetron sputtering technique. A comparison of the properties of the films deposited on polymer and glass substrates was performed. In addition, the effect of the sputter power on the structural and optical properties of these films was evaluated.