• Current Photovoltaic Research
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• 제1권1호
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• pp.27-32
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• 2013

We investigated the growth mechanism of amorphous-phase Si thin films in order to improve the film characteristics and circumvent photo-degradation effects by implementation of hot-wire chemical vapor deposition. Amorphous silicon thin films grown in a silane/hydrogen mixture can be decomposed by a resistive heat filament. The structural properties were observed by Raman spectroscopy, FTIR, SEM, and TEM. The electrical properties of the films were measured by photo-conductivity, dark-conductivity, and photo-sensitivity. The contents of Si-H and $Si-H_n$ bonds were measured to be 19.79 and 9.96% respectively, at a hydrogen flow rate of 5.5 sccm, respectively. The thin film has photo-sensitivity of $2.2{\times}10^5$ without a crystalline volume fraction. The catalyst behavior of the hot-wire to decompose the chemical precursors by an electron tunneling effect depends strongly on the hydrogen mixture rate and an amorphous Si thin film is formed from atomic relaxation.

• 전자공학회논문지A
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• 제31A권6호
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• pp.88-97
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• 1994

We describe the design, fabrication, and performance of the optical fiber-photodiode 1$\times$12 arry module using mesa-type InS10.53T GaS10.47TAS/INP 1$\times$12 PIN photodiode array. We fabricated the PIN PD array for high-speed optical fiber parallel data link optimizing quantum efficiency, operating speed sensitivity from the PIN-FET structure, and electrical AC crosstalk. For each element of the array, the diameter of the photodetective area is 80 $\mu$m, the diameter of the p-metal pad is 90 $\mu$m, and the photodiode seperation is 250 $\mu$m to use Si v-groove. Ground conductor line is placed around diodes and p-metal pads are formed in zigzag to reduce Ac capacitance coupling between array elements. The dark current (IS1dT) is I nA and the capacitance(CS1pDT) is 0.9 pF at -5 V. No signifcant variations of IS1dT and CPD from element to element in the array were observed. We calulated the coupling efficiency for 10/125 SMF and 50/125 GI MMF, and measured the responsivity of the PD array at the wavelength is 1.55 $\mu$ m. Responsivities are 0.93 A/W for SMF and 0.96 A/W for MMF. The optical fiber-PD array module is useful in numerous high speed digital and analog photonic system applications.

• 한국전기전자재료학회논문지
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• 제16권9호
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• pp.812-815
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• 2003

In this study, the MgO thin-film passivation layer was adopted to protect passive matrix organic light emitting diode(PMOLED) with the cathode separator from moisture and oxygen. Using the substrate rotate and tilt technique during the deposition, the organic and cathode layers were perfectly covered with MgO. And then, we analyzed the difference of the current-voltage and luminescence characteristics between passivated OLED of the MgO and non-passivated OLED. It was found that the number of dark spot generated from the degradated pixel was decreased owing to the Mgo thin-film passivation layer using the tilt ＆ rotate technique. And the half-life time passivated OLED was improved two times more. Thus, the MgO could be vaccum-deposited under the low temperature and had a merit that the organic layer was not much affected. We can consider that MgO thin film passivation method can be adopted to protect the OLED from moisture and oxygen and can offer the enhancement of lifetime.

• 천문학회지
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• 제34권2호
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• pp.111-117
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• 2001

Recently, we have set up a new digital CCD camera system, MicroMax YHS-1300 manufactured by Roper Scientific for Ha observation by Solar Flare Telescope at Bohyunsan Optical Astronomy Observatory. It has a 12 bit dynamic range, a pixel number of 1300$\times$1030, a thermoelectric cooler, and an electric shutter. Its readout speed is about 3 frames per second and the dark current is about 0.05 e-/p/s at $-10^{\circ}C$. We have made a system performance test by confirming the system linearity, system gain, and system noise that its specification requires. We have also developed a data acquisition software which connects a digital camera con-troller to a PC and acquires H$\alpha$ images via Microsoft Visual C++ 6.0 under Windows 98. Comparisons of high quality H$\alpha$ images of AR 9169 and AR 9283 obtained from SOFT with the corresponding images from Learmonth Solar Observatory in Australia confirm that our H$\alpha$ digital observational system is performed properly. Finally, we present a set of H$\alpha$ images taken from a two ribbon flare occurred in AR 9283.

• 천문학회보
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• 제37권2호
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• pp.205.2-205.2
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• 2012

MIRIS (Multipurpose Infra-Red Imaging System), the main payload of STSAT-3 (Science and Technology Satellite-3), is the first Korean Infrared Space Telescope developed by KASI (Korea Astronomy and Space Science Institute). The FM (fight model) of MIRIS has been recently completed, and various performance tests have been made to measure system parameters such as readout noise, system gain, linearity, and dark current. The MIRIS FM has been integrated to the satellite system for the environment tests scheduled in September 2012. The MIRIS is expected to be launched in November 2012.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.162-165
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• 2000

To investigate the effect of metal electrode in electroluminescent[EL] devices, we fabricated EL devices of ITO/P3HT/Al, ITO/P3HT/LiF/Al and ITO/P3HT/Mg:In structure. In current-voltage-light power characteristics, turn-on voltage of EL devices using LiF insulating layer and Mg:In(2.8V) metal electrode is lower than EL device using Al(4.2V). Besides the external quantum efficiency is improved also. The reason is related to carrier mobility and carrier injection, which would affect the hole-electron balance. In the device with Al electrode, holes injected from indium-tin-oxide[ITO] to poly(3-hexylthiophene)[P3HT] might reach the Al electrode without interacting with injected electrons, because the electron injection efficiency was very low for this electrode. Besides oxidation of the Al electrode is likely due to holes reaching the cathode without meeting injected electrons. Another possible reason for the higher EL efficiency may be the insulating layer playing the role of a tunneling barrier for holes to the Al electrode. In all EL devices, the orange-red light was clearly visible in a dark room. Maximum peak wavelength of EL spectrum emitted at 640nm in accordance with photon energy 1.9eV

• 센서학회지
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• 제2권1호
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• pp.29-34
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• 1993

본 연구에서는 영상센서를 위해 a-Si : H 광다이오드를 제작하고 그 특성을 조사하였다. a-SiN : H와 p-a-Si : H막의 차단층이 없는 ITO/a-Si : H/Al 광다이오드의 광감도는 5 V의 인가전압에서 0.7로 나타났으며 가시광영역에서의 분광감도는 620 nm의 파장에서 가장 높게 나타났다. ITO/a-SiN : H/a-Si : H/p-a-Si : H/Al 광다이오드의 암전류는 정공차단막과 전자차단막의 작용으로 인하여 10V의 인가전압까지 1.5pA이하로 억제되었다. 또한 광감도는 3 V의 인가전압에서 약 1로 가장 높게 나타났으며 분광감도는 540 nm의 파장에서 최대응답을 보였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.345-345
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• 2007

본 연구는 x선 영상검출기 적용을 위한 $HgI_2$ 필름의 누설전류 특성 향상을 위한 연구로서, $HgI_2$기반의 다양한 물질을 이용하여 다층구조 방식으로 제작된 필름의 누설전류 특성평가 및 제작된 다층구조의 상부전극물질의 변화에 따른 누설전류 특성을 평가하였다. $HgI_2$기반 다층구조의 제작 물질은 Parylene, $PbI_2$, a-Se을 사용하여 시편(parylene/ITO, ITO/$HgI_2/PbI_2$/ITO, ITO/$HgI_2$/a-Se/ITO)을 제작하였으며, 필름 제작공정은 Screen print, PVD공정으로 다층구조 필름을 제작하였다. 또 한, 다층구조로 제작된 필름에 상부 전극물질은 Au, In, ITO를 사용하여 누설전류의 특성을 평가하였다. 측정 장치로 DC Power Supply(556H. EG&G : 50~200V), X 선 발생장치(Toshiba KXO-50N), 차폐체 (Al 및 Cu), Oscilloscope (LeCroy, LC334AM, USA), Electrometer (Keithley, 6517), Ion chamber 2060 (Radical Co.)을 이용하여, 제작된 $HgI_2$기반 다층구조 sample의 누설전류 특성을 실험하였다. 이 결과로 다층구조에 제작된 물질 및 상부전극에 따른 누설전류의 특성을 평가하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.13-16
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• 2004

The reliability of 1.550m-wavelength InGaAs mesa waveguide photodiodes(WGPDs), which developed for 40-Gbps optical receiver applications, fabricated by metal organic chemical vapor deposition is investigated. Reliability is examined by both high-temperature storage tests and the accelerated life tests by monitoring dark current and breakdown voltage. The median device lifetime and the activation energy of the degradation mechanism are computed for WGPD test structures. From the accelerated life test results, the activation energy of the degradation mechanism and median lifetime of these devices in room temperature are extracted from the log-normal failure model by using average lifetime and the standard deviation of that lifetime in each test temperature. It is found that the WGPD structure yields devices with the median lifetime of much longer than $10^6$ h at practical use conditions. Consequently, this WGPD structure has sufficient characteristics for practical 40-Gbps optical receiver modules.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.263-266
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• 2004

The stochiometric mix of evaporating materials for the $ZnGa_2Se_4$ single crystal thin films were prepared from horizental furnace. The polycrystal structure obtaind from the power x-ray diffraction was defect chalcopyrite. The lattice costants $a_0\;and\;c_0\;were\;a_0=5.51\;A,\;c_0=10.98\;A$. To obtains the single crystal thin films, $ZnGa_2Se_4$ mixed crystal were deposited on throughly etched Si(100) by the Hot Wall Epitaxy (HWE) system. The temperates of the source and the substrate were $590^{\circ}C\;and\;450^{\circ}C$, respectively. The crystalline structure of single crystal thin films was investigated by the double crystal X-ray diffraction(DCXD). Hall effect on this sample was measured by the method of van der Pauw and studied on carrier density and mobility dependence on temperature. In order to explore the applicability as a photoconductive cell, we measured the sensitivity($\gamma$), the ratio of photocurrent to dark current(pc/dc), maximum allowable rower dissipation(MAPD), spectral response and response time.