• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 추계학술대회 논문집
• /
• pp.505-508
• /
• 2001

Currently there is much interested in removing latent charge that is caused to latent image effect and blurring of obtained image as well as reduction of x-ray conversion efficiency in digital radiography system. To remove latent charge a-Se film is irradiated by light with 3500 lux using halogen lamp and optical fiber. We measured dark current and photosensitivity to analyze removing effect of latent charge, then compared with and without light erasing method. The reduction of measured signal due to latent charge effect was 32.3%, and the removal effect of latent charge by using light erase method was its 95.5%.

• 전자공학회논문지A
• /
• 제31A권12호
• /
• pp.16-22
• /
• 1994

In this paper, transmitter and receiver modules for free space optical interconnection are implemented and characterized. In the transmitter module, bias circuitry which inject current into the direct modulated laser diode is fabricated and in the receiver module, p-i-n diode is integrated with an MMIC amplifying stage. Laser diode has a direct-modulated bandwidth of 2 GHz at 1.4 Ith bias while p-i-n diode and amplifying stage has a bandwidth of 1.3 GHz and 1.5 GHz, repectively. Optical interconnection has a bandwidth of 1.3 GHz and linearly transmit modulated voltage signal up to 1.5 Vp-p. Measured loss of optical interconnection is 5dB which is composed of optoelectronic conversion loss of 15 dB, electrical impedance mismatch loss of 6.7 dB in transmitter module and gain of 18 dB in receiver module. Seperation between transmitter and receiver can be extended up to 50 cm by using a lens.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2000년도 추계학술발표대회 논문집
• /
• pp.124-127
• /
• 2000

In this study, a technique for monitoring of fatigue damage of composite laminates by measuring the stiffness change using embedded intensity-based optical fiber sensors was investigated. Firstly, the underlying measurement principle and structure of intensity-based sensors and then a simple stiffness conversion process was explained. The monitoring technique was evaluated by fatigue tests of composite laminates with an embedded intensity-based sensor. From the test results, the response of the intensity-based sensor showed good correlation with that of surface mounted extensometer. Therefore, it can be concluded that the intensity-based sensors have good potential for the monitoring of fatigue damage of composite structures under fatigue loading. In addition, it could be confirmed that the intensity-based sensors have higher resistance to fatigue than the commercial electrical strain gauge.

• Transactions on Electrical and Electronic Materials
• /
• 제14권4호
• /
• pp.177-181
• /
• 2013

In this paper, silicon solar cells are analyzed regarding power conversion efficiency by changed capacitance in the depletion region. For the capacitance control in the depletion region of silicon solar cell was applied for 10, 20, 40, 80, 160 and 320 Hz frequency band character and alternating current(AC) voltage with square wave of 0.2~1.4 V. Academically, symmetry formation of positive and negative change of the p-n junction is similar to the physical effect of capacitance. According to the experiment result, because input of square wave with alternating current(AC) voltage could be observed to changed capacitance effect by indirectly method through non-linear power conversion (Voltage-Current) output. In addition, when input alternating current(AC) voltage in the silicon solar cell, changed capacitance of depletion region with the forward bias condition and reverse bias condition gave a direct effect to the charge mobility.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 하계학술대회 논문집
• /
• pp.288-288
• /
• 2009

We have studied polarity effects of dielectric anisotropy effects on electro-optical characteristics of a twisted nematic mode driven by fringe electric field, which has wide viewing angle characteristics. Our device is designed as normally black mode between parallel polarizers. The perfect polarization conversion of incident light, which passes through a polarizer, is achieved, when it passes through the twisted liquid crystal (LC) layer. If an electric field is applied, the LC molecules with a positive (or negative) dielectric anisotropy rotate parallel (or perpendicular) to the horizontal component of a fringe electric field as increasing transmittance. From the calculated results, enhanced transmittance of the fringe field-twisted nematic (FF-TN) mode with positive dielectric anisotropy of + 8.2 can be obtained.

• 한국전기전자재료학회논문지
• /
• 제18권3호
• /
• pp.226-230
• /
• 2005

This paper describes the photocatalytic degradation properties by oxygen partial pressure for TiO$_2$ thin films fabricated by dc magnetron reactive sputtering. And the structural, chemical, optical and photocatalytic properties were investigated at various analysis system. When TiO$_2$ thin film was made at deposition time of 120 min and Ar:O$_2$ ratio of 60:40, the best properties were obtained. That results were as follows: thickness; 360∼370 nm, gram size; 40 nm, optical energy band gap; 3.4 eV and Benzene conversion in the photocatalytic degradation; 11 %.

• 대한전자공학회논문지
• /
• 제23권4호
• /
• pp.498-505
• /
• 1986

In2O3: Sn(ITO) transparent conducting films were fabricated by the electron beam evaporation method. The dependence of their electrical and optical properties on deposition conditions were examined. The optimum evaporation conditions were such that the deposition rate was 5-10\ulcornersec, oxygen partial pressure was 4x10**_4 torr, substate temperatudre was above 300\ulcorner, and SnO2 doping rate was 10 mol%. The values of sheet resistance and transmittance of the films in visible region fabricated under these optimum conditins were 12\ulcorner/ and 87-99%, respecively. And the energy conversion efficiency of the SIS solar cell fabricated using ITO was 9.16%. It is shown that the transparent conducting films can be applied to the TV camear pick-up tube and solar cell.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.377-377
• /
• 2016

Under nanosecond-pulsed laser irradiation, light-absorbing thin films have been used for photoacoustic transmitters for ultrasound generation. Especially, nanostructured absorbers are attractive due to high optical absorption and efficient thermoacoustic energy conversion: for example, 2-dimensional (2-D) gold nanostructure array, synthetic gold nanoparticles, carbon nanotubes (CNTs), and reduced graphene oxides. Among them, CNT has been used to fabricate a composite film with polydimethylsiloxane (PDMS) that exhibits excellent photoacoustic conversion performance for high-frequency, high-amplitude ultrasound generation. Previously, CNT-PDMS nanocomposite films were made by using a high-temperature chemical vapor deposition (HTCVD) process for CNT growth. However, this approach is not suitable to fabricate large-area CNT films (>several cm2). This is because a chamber dimension of HTCVD is limited and also the process often causes nonuniform CNT growth when the film area increases. As an alternative approach, a solution-based process can be used to overcome these issues. We develop PDMS composite transmitters, based on the solution process, using several nanostructured light-absorbers such as CNTs, nanoink powders, and imprinted regular arrays of gold nanostructure. We compare fabrication processes of each composite transmitters and photoacoustic output performance.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 하계학술대회 논문집 C
• /
• pp.1645-1647
• /
• 1996

Polycrystalline CdTe thin films -have been studied for photovoltaic application because of their high absorption coefficient and optimal band gap energy (1.54 eV) for solar energy conversion. In this study, we prepared CdTe films using RF-magnetron sputtering method and investigated structural, optical and electrical properties with spectrophotometer, XRD, EDX, and resistivity meter. CdTe films at $200\;^{\circ}C$ showed a mixture of zinc blend (Cubic) and wurtzite (hexagonal) phase. On the other hand, the films at $400\;^{\circ}C$ showed highly oriented structure having hexagonal structure. The resistivity of CdTe films deposited on $SiO_2$ substrates was about $10_7\;{\Omega}cm$. The value of resistivity decreased with the increase of the substrate temperature. CdTe were sputtered on CdS thin films prepared by chemical bath deposition for the formation of the heterojunction. I-V characteristics of these cells were measured at a light density of $100mw/cm^2$, AM. 1.0. The present thin film solar cells showed a conversion efficiency of about 5%.

• 한국광학회지
• /
• 제31권1호
• /
• pp.37-44
• /
• 2020

본 연구에서는 기본적인 평면 태양 전지 구조에 1차원 주기를 가지는 에미터 전극 배치를 통해 광학 및 전기적 효율을 최적화하는 설계방법을 제안한다. 에미터 전극의 주기가 줄어들면 애퍼처 비율이 감소해 빛 흡수율이 줄어들어 태양 전지 성능 저하에 영향을 끼친다. 본 연구에서는 시뮬레이션을 통해 가장 간단한 평판형 태양 전지 구조 내에서 에미터 전극 배열의 최적안을 제시하였다. 광학적 측면에서 에미터 전극이 없이 광흡수층 전면에서의 광흡수를 하는 레퍼런스 소자와 성능이 유사한 조건을 도출했다. 그리고 광흡수 및 전기적 효율 측면을 모두 고려하여 가장 효과적인 전극 구조를 제안하였다. 본 연구 결과는 광전 변환으로 생성된 전하를 전극으로 가장 효율적으로 전달할 수 있는 구조를 제안함으로써, 대체 에너지원에서 큰 비중을 차지하고 있는 태양 전지의 활용성을 높이는데 기여할 것이다.