• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.202-205
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• 2002

The photoluminescence (PL) characteristics of the silicon-oxygen(Si-O) superlattice formed by molecular beam epitaxy (MBE) were studied. To confirm the presence of the nanocrystalline Si structure, Raman scattering measurement was performed. The blue shift was observed in the PL peak of the oxygen-annealed sample, compared to the hydrogen-annealed sample, which is due to a contribution of smaller crystallites. Our results determine the right direction for the fabrication of silicon-based optoelectronic and quantum devices as well as for the replacement of silicon-on-insulator (SOI) in high-speed and low-power silicon MOSFET devices in the future.

• 한국고분자학회지:고분자과학과기술
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• 제24권2호
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• pp.159-164
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• 2013

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.602-604
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• 2004

NPB surface morphologies deposited on different temperature substrates were investigated using atomic force microscopy(AFM). It has been found that the NPB morphology turned from island morphology at high temperature(100$^{\circ}C$) to grain morphology at room temperature. To characterize the effect of NPB surface morphology, the devices with the structure of Glass/ITO/NPB/$Alq_3$/Al were fabricated using NPB films deposited at different substrate temperature and their performances were compared.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.233-233
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• 2006

• 전자공학회논문지A
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• 제28A권5호
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• pp.370-374
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• 1991

A high performance fully ion-implanted InP JFET was characterized for high speed switching elements. The switch has an insertion loss of 5.5dB with 31.6dB isolation at 1GHz. This device can effectively swithc a byte-multiplexed 2Gb/s signal and an eye-diagram taken at 2Gb/s shows an error-free eye pattern. Therefore, this device can be used as a switching element for high transmission data rate for monolithic integration of optoelectronic circuit in the long-wavelength region.

• 센서학회지
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• 제32권6호
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• pp.391-402
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• 2023

Low-dimensional (zero-dimensional (0-dim), 2-dimensional (2-dim)) nanoparticles, such as chalcogenide compound semiconductors, III-V semiconductors, transition metal dichalcogenides (TMDs), II-VI semiconductors, nanocarbons, hybrid quantum dots (QDs), and perovskite QDs (PQDs), for which blue light emission has been observed, are reviewed. Current synthesis and device fabrication technologies as well as their prospective applications on next-generation quantum-dot-based light-emitting diodes are discussed.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권4호
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• pp.483-491
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• 2017

The interdigitated germanium (Ge) meta-lsemiconductor-metal (MSM) photodetectors (PDs) with and without an $SiO_2$ anti-reflection (AR) layer was fabricated, and the effect of $SiO_2$ AR layer on their optoelectronic response properties were investigated in detail. The lowest reflectance of 15.6% at the wavelength of 1550 nm was obtained with a $SiO_2$ AR layer with a thickness of 260 nm, which was in a good agreement with theoretically calculated film thickness for minimizing the reflection of Ge surface. The Ge MSM PD with 260 nm-thick $SiO_2$ AR layer exhibited enhanced device performance with the maximum values of responsivity of 0.65 A/W, the quantum efficiency of 52.2%, and the detectivity of $2.49{\times}10^9cm\;Hz^{0.5}W^{-1}$ under the light illumination with a wavelength of 1550 nm. Moreover, time-dependent switching analysis of Ge MSM PD with 260 nm- thick $SiO_2$ AR layer showed highest on/off ratio with excellent stability and reproducibility. All this investigation implies that 260 nm-thick $SiO_2$ AR layer, which is effective in the reduction in the reflection of Ge surface, has a great potential for Ge based optoelectronic devices.

• 한국전기전자재료학회논문지
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• 제32권5호
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• pp.418-425
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• 2019

A piezoelectric ceramic fiber composite (PCFC) was successfully fabricated using $0.69Pb(Zr_{0.47}Ti_{0.53})O_3-0.31[Pb(Zn_{0.4}Ni_{0.6})_{1/3}Nb_{2/3}]O_3$ (PZT-PZNN) for use in small-scale wind energy harvesters. The PCFC was formed using an epoxy matrix material and an array of Ag/Pd-coated PZT-PZNN piezo-ceramic fibers sandwiched by Cu interdigitated electrode patterned polyethylene terephthalate film. The energy harvesting performance was evaluated in a custom-made wind tunnel while varying the wind speed and resistive load with two types of flutter wind energy harvesters. One had a five-PCFC array vertically clamped with a supporting acrylic rod while the other used the same structure but with a five-PCFC cantilever array. Stainless steel (thickness: $50{\mu}m$) was attached onto one side of the PCFC to form the PZT-PZNN cantilever. The output power, in general, increased with an increase in the wind speed from 2 m/s to 10 m/s for both energy harvesters. The highest output power of $15.1{\mu}W$ at $14k{\Omega}$ was obtained at a wind speed of 10 m/s for the flutter wind energy harvester with the PZT-PZNN cantilever array. The results presented here reveal the strong potential for wind energy harvester applications to supply sustainable power to various IoT micro-devices.

• 청정기술
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• 제22권3호
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• pp.203-207
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• 2016

Here, we report a novel fabrication technique for patchable organic lasing sheet based on non-volatile liquid organic semiconductors and freestanding polymeric film with high flexibility and patchability. For this work, we have fabricated the second-order DFB grating structure, which leads to surface emission, embedded in the freestanding polymeric film. Using an ultra-violet (UV) curable polyurethaneacrylate (PUA) mixture, the periodic DFB grating structure can be easily prepared on the freestanding polymeric film via a simple UV curing process. Due to unsaturated acrylate remained in the PUA mixture after UV curing, the freestanding PUA film provides adhesive properties, which enable mounting of the patchable organic lasing sheet onto non-flat surfaces with conformal contact. To achieve laser actions in the freestanding resonator structure, a composite material of liquid 9-(2-ethylhexyl)carbazole (EHCz) and organic laser dyes was used as the laser medium. Since the degraded active materials can be easily refreshed by a simple injection of the liquid composite, such a non-volatile liquid organic semiconducting medium has degradation-free and recyclable characteristics in addition to other strong advantages including tunable optoelectronic responses, solvent-free processing, and ultimate mechanical flexibility and uniformity. Lasing properties of the patchable organic lasing sheet were also investigated after mounting onto non-flat surfaces, showing a mechanical tunability of laser emission under variable surface curvature. It is anticipated that these results will be applied to the development of various patchable optoelectronic applications for light-emitting displays, sensors and data communications.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.253-253
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• 2011

ZnTe semiconductor is very attractive a material for optoelectronic devices in the visible green spectral region because of it has direct bandgap of 2.26 eV. The prototypes of ZnTe light emitting diodes (LEDs) have been reported [1], showing that their green emission peak closely matches the most sensitive region of the human eye. The optoelectronic properties of ZnTe:O film allow to expect a large optical gain in the intermediate emission band, which emission band lies about 0.4-0.6 eV below the conduction band of ZnTe [2]. So, the ZnTe system is useful for the production of high-efficiency multi-junction solar cells [2,3]. In this work, the ZnTe:O thin films were deposited on Al2O3 substrates by using the radio frequency magnetron sputtering system. Three sets of samples were prepared using argon and oxygen as the sputtering gas. The deposition chamber was pre-pumped down to a base pressure of 10-7 Torr before introducing gas. The deposition pressure was fixed at 10-3 Torr throughout this work. During the ZnTe deposition, the substrate temperature was 300 oC. The optical properties were also investigated by using the ultraviolte-visible (UV-Vis) spectrophotometer.