• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.10
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• pp.648-651
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• 2015

The characterizations of zinc oxide (ZnO) buffer layers grown by unbalanced magnetron (UBM) sputtering under various substrate temperatures for inverted organic solar cells (IOSCs) were investigated. UBM sputter grown ZnO films exhibited higher crystallinity with increasing the substrate temperature, resulting in uniform and large grain size. Also, the electrical properties of ZnO films are improved with increasing substrate temperature. In the results, the performance of IOSCs critically depended on the substrate temperature during the film growth because the crystalllinity of the ZnO film affect the carrier mobility of the ZnO film.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.97-100
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• 2000

Bi$_2$Sr$_2$CuO$\sub$x/(Bi(2201)) thin films are fabricated by atomic layer by layer deposition using ion beam sputtering(IBS) method. During the deposition, 10 %-ozone/oxygen mixture gas of typical 5.0 ${\times}$ 10$\^$-5/. Torr is applied with ultraviolet light irradiation for oxidation. XRD and RHEED investigations reveal out that a buffer layer with some different compositions is formed at the early deposition stage of less than 10 units cell and then c-axis oriented Bi(2201) is grown.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.25-28
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• 2000

In this study, Transient Characteristics of the Punch-Through Insulated Gate Bipolar Transistor (PT-IGBT) has been studied. On the contraty to Non-Punch Through Insulated Gate Bipolar Transistor(NPT-IGBT), PT-IGBT has buffer layer It has a simple drive circuit controlled by the gate voltage of the MOSFET and the low on-state resistance of the bipolar junction transistor. In this paper, the transient characteristics with temperature of the PT-IGBT has been analyzed analytically. PT-IGBT is made to reduce switching power loss. Excess Minority carrier distribution inactive base region and base charge, the rate of voltage with time is expressed analytically to include buffer layer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.67-69
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• 2004

The $Pb(Zr,Ti)O_3$ thin films were fabricated with $Pb(La,Ti)O_3$ buffers in-situ onto $Pt/Ti/SiO_2/Si$ substrates by pulsed laser deposition technique using a Nd:YAG laser with energy density of $2.5J/cm^2$, and deposited for 10 minutes at $550^{\circ}C$ of substrate temperature. And then, the films have been annealed at $550^{\circ}C$ in oxygen ambient pressure. The remanent polarization value is increased by using buffer layers but coercive field of films is slightly increased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.322-323
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• 2005

We deposited Zinc oxide (ZnO) thin films on Ru buffer layer in order to protect the amorphous layer between ZnO and Al interface. In X-ray diffraction (XRD) pattern, it was observed that increase of (002)-orientation by the variation of annealing treatment temperature. Also, surface roughness and specific resistance were increased by annealing treatment but full width at half maximum (FWHM) was decreased. In film bulk acoustic resonators (FBARs) fabricated from these results, we finally confirmed that the resonant frequency of 0.89 GHz without its shift was measured.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1089-1091
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• 2004

본 연구에서는 fiexible 기판에 e-beam으로 sio2를 증착 한 후 R.F 스퍼터링으로 ito 박막을 증착한 경우와 polyimide를 스핀 코팅한 후 ito를 증착한 경우로 나누어서 실험 하였다. SIO2 박막은 ITO증착을 위해 증착온도 $100^{\circ}C$에서 증착 하였으며 ITO 박막은 투과율을 향상 시키기 위해서 Ar/O2 혼합가스를 이용하였다. SIO2 와 ITO 박막의 두께는 각각 500nm, 200nm로 증착하였다. Stress 분포는 bending test를 통해 발생하는 island의 crackt 수로 측정 하였다. 그 결과 crack 분포는 buffer layer의 young's modulus 크기와 island density 영향이 지배적임을 확인 하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.1
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• pp.36-41
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• 2023

We investigated the properties of vanadium oxide (VOx) buffer layers deposited by a dual RF magnetron sputtering method under various target powers for inverted organic solar cells (IOSCs). Sputter fabricatged VOx thin films exhibited higher crystallinity with the increase of target power, resulting in a uniform and large grain size. The electrical properties of VOx films are improved with the increase of target power because of the increase of V content. In the results, the performance of IOSCs critically depended on the target power during the film growth because the crystalllinity of the VOx film affects the carrier mobility of the VOx film.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.4
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• pp.327-329
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• 2005

Pb(Zr/sub 0.52/Ti/sub 0.48/)O₃(PZT) thin films were deposited by using a pulsed laser deposition method on a Pt/Ti/SiO₂/Si substrate with (Pb/sub 0.72/La/sub 0.28/)Ti/sub 0.93/O₃ (PLT) buffer and on a Pt/Ti/SiO₂/Si substrate without buffer. These films were annealed in H₂-contained ambient for 30 minutes at the substrate temperature of 400。C to evaluate the forming gas annealing effects. The comparative studies on the ferroelectric properties of these two films were carried out, which are shown that ferroelectric properties, such as remanent polarization didn't change in the case of PLT buffered PZT film while remanent polarization value of PZT film degraded from 20.8 C/㎠ to 7.3 C/㎠. The leakage current became higher in both cases, but that of the more-oriented PZT film had the moderate value of the 10/sup -6/ order of A/㎠. This is mainly because the hydrogen atoms which make the degradation of PZT films cannot infiltrate into the more -oriented PZT film as well as the less-oriented PZT film.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.399-402
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• 1998

Electroluminescent(EL) devices based on organic thin films have attracted lots of interests in large-area light-emitting display. One of the problems of such device is a lifetime, where a degradation of the cell is possibly due to an organic layers thickness, morphology and interface with electrode. In this study, light-omitting organic electroluminescent devices were fabricated using Alq$_3$(8-hydroxyquinolinate aluminum) and TPD(N,N'-diphenyl-N,N'-bis(3-methylphenyl(1-1\`-biphenyl]-4,4'-diamine). Where Alq$_3$ is an electron-transport and emissive layer, TPD is a hole-transport layer. The cell structure is ITO/TPD/Alq$_3$/Al and the cell is fabricated by vacuum evaporation method. In a measurement of current-voltage characteristics, we obtained a turn-on voltage at about 9 V. We also investigated stability of the devices using buffer layer with blend of PEI (Poly ether imide) and TPD by varying mot ratios between ITO and Alq$_3$. In current-voltage characteristics measurement, we obtained the turn-on voltage at about 6 V and observed an anomalous behavior at 3∼4 V. And we used other buffer layer of PEDT(3,4-pyrazino-3',4'-ethylenedithio-2,2',5,5'-tetrathiafulvalenium) with ITO/PEDT/TPD/Alq$_3$Al structure. We observed a surface morphology by AFM(Atomic Force Microscopy), UV/visible absorption spectrum, and PL(Photoluminescence) spectrum. We obtained the UV/visible absorption peak at 358nm in TPD and at 359nm in Alq$_3$, and the PL peaks at 410nm in TPD and at 510nm in Alq$_3$. We also studied EL spectrum in the cell structure of ITO/(TPD+PEI)/Alq$_3$/Al.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.334-334
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• 1999