• Proceedings of the Materials Research Society of Korea Conference
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• 2001.11a
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• pp.70-70
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• 2001

• Journal of the Korean Vacuum Society
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• v.17 no.2
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• pp.96-101
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• 2008

The magnesium oxide (MgO) protective layer plays an important role in plasma display panels (PDPs). Our previous work demonstrated that the properties of MgO thin film could be improved, which were deposited by Ion-Beam-Assisted Deposition (IBAD). However arc discharge always occurs during the IBAD process. To avoid this problem, Oxygen-Neutral-Beam-Assisted Deposition (NBAD) is used to deposit MgO thin films in this paper. The energy of the oxygen neutral beam was used as the parameter to control the deposition. The experimental results showed that the oxygen neutral beam energy was effective in determining in structural and discharge characteristics. The lowest firing inception voltage, the highest brightness and the highest luminous efficiency were obtained when the MgO thin film was deposited with an oxygen neutral beam energy of 300eV. The surface morphology of MgO thin film was also analyzed using AFM (Atomic Force Microscopy) and SEM (Scanning Electron Microscopy).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.87-88
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• 2008

In the structure of ITO/N,N'-diphenyl-N,N' bis (3-methylphenyl)-1,1'-biphenyl-4,4'-diamine(TPD)/tris (8-hydroxyquinoline)aluminum$(Alq_3)$/Al device, we studied the efficiency improvement of organic light-emitting diodes due to variation of deposition rate of TPD materials. The thickness of TPD and $Alq_3$ was manufactured 40 nm, 60 nm, respectively under a base pressure of $5\times10^{-6}$Torr using a thermal evaporation. The $Alq_3$ used for an electron-transport and emissive layer were evaporated to be at a deposition rate of 2.5 $\AA$/s. When the deposition rate of TPD increased from 1.5 to 3.0 $\AA$/s, we found that the average roughness is rather smoother, external quantum efficiency is superior to the others when the deposition rate of TPD is 2.5 $\AA$/s. Compared to the ones from the devices made with the deposition rate of TPD 3.0 $\AA$/s, the external quantum efficiency was improved by a factor of eight.

• Korean Journal of Materials Research
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• v.33 no.11
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• pp.491-496
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• 2023

As the demand for p-type semiconductors increases, much effort is being put into developing new p-type materials. This demand has led to the development of novel new p-type semiconductors that go beyond existing p-type semiconductors. Copper iodide (CuI) has recently received much attention due to its wide band gap, excellent optical and electrical properties, and low temperature synthesis. However, there are limits to its use as a semiconductor material for thin film transistor devices due to the uncontrolled generation of copper vacancies and excessive hole doping. In this work, p-type CuI semiconductors were fabricated using the chemical vapor deposition (CVD) process for thin-film transistor (TFT) applications. The vacuum process has advantages over conventional solution processes, including conformal coating, large area uniformity, easy thickness control and so on. CuI thin films were fabricated at various deposition temperatures from 150 to 250 ℃ The surface roughness root mean square (RMS) value, which is related to carrier transport, decreases with increasing deposition temperature. Hall effect measurements showed that all fabricated CuI films had p-type behavior and that the Hall mobility decreased with increasing deposition temperature. The CuI TFTs showed no clear on/off because of the high concentration of carriers. By adopting a Zn capping layer, carrier concentrations decreased, leading to clear on and off behavior. Finally, stability tests of the PBS and NBS showed a threshold voltage shift within ±1 V.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.201-202
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• 2003

We developed a novel growth method of aligned carbon nanotubes. Aligned carbon nanotubes are grown on a metal catalyst on a glass substrate using biased Helicon plasma chemical vapor deposition (HPECVD) of $CH_4/H_2$ gases from 400 C to 500 C. The Helicon plasma source is one of the high-density plasma sources and is promising for low temperature carbon deposition. A Ni film was used as a catalyst to reduce the activation energy of the nanotubes' growth. The carbon nanotubes were deposited on the nickel catalysis layer selectively.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.897-900
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• 2003

Chemical vapor condensation (CVC) reactor was investigated for the deposition of Parylene-N thin films as the passivation layer for organic light emitting diodes (OLEDs). Several gas inlet manifold designs were tested to improve the deposition rate and its uniformity, and it was found that proper inlet design is crucial to get the desired film properties. Process characterization was also performed with the modified inlets to optimize the process variables.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.415.1-415.1
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• 2016

2009년도에 Perovskite가 태양전지에 처음 적용된 이후, Perovskite를 기반으로 하는 태양전지는 급속한 발전을 이루고 있으나, 향후 상용화를 위해서는 추가적인 공정개선 및 제조 단가를 낮추는 노력이 필수적이다. 초창기 Perovskite의 증착 공정은 One step deposition 방법이 사용되었으나, Layer의 thickness, uniformity 등을 조절하기 어려워 Sequential deposition 방법으로 개선되었다. 하지만 결과적으로 초기방법 대비 추가공정이 발생함에 따라 시간 및 비용의 증가가 불가피하였다. 제조단가 측면에서는 Perovskite 태양전지를 구성하는 재료 중 HTM(정공수송물질)을 구성하는 Spiro-MeOTAD의 비용이 가장 비싸다. 따라서 저비용 태양전지를 위해서는 HTM이 없는 구조가 필요하다. 이 페이퍼에서는 Perovskite 물질이 고흡광 능력 외에 충분한 전하수송능력을 보유한다는 점에 착안하여, Gas Pressure Assisted Modified One Step Deposition을 이용한 HTM Free Perovskite를 제작하고 기존의 Sequential Deposition Method 통해 만들어진 Perovskite 태양전지와 비교/분석하였다.

• Journal of Environmental Impact Assessment
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• v.8 no.1
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• pp.1-16
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• 1999

The acid deposition and photochemical modeling study was performed on the Eastern Asia using Regional Acid Deposition Model(RADM). The results of this study show that horizontal distribution of $SO_2$, concentration and dry deposition flux was higher in Beking, Shanghai and central part of Korea. However distribution pattern of sulfate and $O_3$ concentration calculated by RADM were not similar to emission pattern. In daytime, $SO_2$, sulfate and $O_3$ were mixed to whole PBL but in nighttime because of inversion layer these pollutants were suppressed to lower level.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.12
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• pp.573-578
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• 2003

In this study, new type of induction charging system for electrostatic spraying was manufactured and proposed to improve the electrical safety and charging efficiency. And parameters of proposed system to generate the maximum deposition current with electrical safety were selected and investigated. The selected parameters were frequency of square pulse and thickness of insulation material, outer diameter of device and thickness and positions of electrode. Charging quantity of water drop was measured by deposition current detected from sensing plate indirectly. The maximum deposition current for each parameter were 3.5[uA] at the frequency of 15[kHz] and thickness of 0.25[mm] insulating layer. And maximum deposition currents were 2.8[uA] and 3.0[uA] at 25[mm] outer diameter of charging device and 0.25[mm] thickness of electrode each. Effects of electrode position from spraying nozzle on deposition current was a little.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.44-47
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• 2004

Fabrication of barrier layer on PES substrate and plastic OLED device by atomic layer deposition are carried out. Simultaneous deposition of 30nm of $AlO_x$ film on both sides of PES gives film MOCON value of 0.0615g/$m^2$.day (@38$^{\circ}C$, 100% R.H). Introduction of conformal $AlO_x$ film by ALD resulted in enhanced barrier properties for inorganic double layered film including PECVO $SiN_x$. Preliminary life time to 91% of initial luminance (1300 cd/$m^2$ ) for 100nm of PECVD $SiN_x$/30nm of ALD $AlO_x$ coated plastic OLED device was 260 hours.