• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.10
• /
• pp.152-159
• /
• 1996

We have designed and implemented an optoelectronic hardware of binary phase extraction joint transform correlator (BPEJTC) which provides higher peak-to-sidelobe ratio than many other versions of JTC that has been published so far and does not produce correlation peaks due to intra-class association, to construct a multi-target tracking system. The digital processing unit controlling the entire system plays the part of modifying and binarizing the joint transform power spectrum (JTPS) and the optical processing unit is mainly used to take fourier transform operations. Some experimental results conducted by designed system along with its architecture showed the processing rate of 6 frames per second, thereby the potential applicability of the proposed system to real-time multitarget tracking system is given.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.8
• /
• pp.2190-2194
• /
• 2010

Development of the methods to organize zeolite microcrystals into closely packed and uniformly aligned monolayers on various substrates have been pursued viewing microparticles as a novel class of building blocks. We now report that the vertically aligned zeolite monolayer can be applied as novel supramolecularly organized systems for anisotropic photoluminescence in high dichroic ratio, to study energy transfer dynamics between the internal and external fluorophores, and to develop zeolite-based advanced materials. Study of polarized fluorescence spectroscopy and angle-dependent intensity change with dye molecules in different surroundings further provides insight into molecular interactions that can be used for the future design of optoelectronic device in nanometer size. In addition, this report shows that isolating of organic dye through surface treatment is crucial for preventing the egress of the incorporated dye molecules from the channels of zeolite to the solution and to enhance the anisotropic luminescence.

• Journal of the Korean Ceramic Society
• /
• v.55 no.2
• /
• pp.108-115
• /
• 2018

The increasing demands for three-dimensional (3D) electronic and optoelectronic devices have triggered interest in epitaxial growth of 3D semiconductor materials. However, most of the epitaxially-grown nano- and micro-structures available so far are limited to certain forms of crystal arrays, and the level of control is still very low. In this review, we describe our latest progress in 3D epitaxy of oxide and nitride semiconductor crystals. This paper covers issues ranging from (i) low-temperature solution-phase synthesis of a well-regulated array of ZnO single crystals to (ii) systematic control of the axial and lateral growth rate correlated to the diameter and interspacing of nanocrystals, as well as the concentration of additional ion additives. In addition, the critical aspects in the heteroepitaxial growth of GaN and InGaN multilayers on these ZnO nanocrystal templates are discussed to address its application to a 3D light emitting diode array.

• Ceramist
• /
• v.22 no.3
• /
• pp.218-229
• /
• 2019

The development of highly efficient thermally activated delayed fluorescence (TADF) materials is an active area of recent research in organic light emitting diodes (OLEDs) since the first report by Chihaya Adachi in 2011. Traditional fluorescent materials can harvest only singlet excitons, leading to the theoretically highest external quantum efficiency (EQE) of 5% with considering about 20% light out-coupling efficiency in the device. On the other hand, TADF materials can harvest both singlet and triplet excitons through reverse intersystem crossing (RISC) from triplet to singlet excited states. It could provide 100% internal quantum efficiencies (IQE), resulting in comparable high EQE to traditional rare-metal complexes (phosphorescent materials). Thanks to a lot of efforts in this field, many highly efficient TADF materials have been developed. This review focused on recent molecular design concept and optoelectronic properties of TADF materials for high efficiency and long lifetime OLED application.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07b
• /
• pp.1383-1385
• /
• 2005

We synthesized new poly(p -phenylene vinylene) (PPV) derivatives including different portions of crosslink that could interconnect the backbone of PPV for application in optoelectronic devices such as lightemitting-diodes, photovoltaic cells, and lasers. The fluorescence and electroluminescence properties of PPV including crosslink were discussed with respect of their structure and length of crosslink unit.

• Journal of Information Display
• /
• v.12 no.4
• /
• pp.205-208
• /
• 2011

Herein, the integration of solution-processed polymer thin-film transistors (TFTs) that were fabricated using selective wettability through ultraviolet (UV) exposure into a reflective liquid crystal display is demonstrated. From the experimental results of energy-dispersive spectroscopy, the composition of carbon and fluorine enhancing the hydrophobicity in the polymer chains was found to play a critical role in the wetting selectivity upon UV exposure. The polymer TFTs fabricated through the wettability-patterning process exhibited long-term stability and reliability. This wetting-selectivity-based patterning technique will be useful for constructing different types of solution-processed electronic and optoelectronic devices.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.2C no.5
• /
• pp.258-261
• /
• 2002

Electrical forming dependent current-voltage (I-V) and numerically derived differential conductance(dI／dV) characteristics have been presented in the multi-layer nano-crystalline silicon／oxygen (no-Si／O) superlattice. Distinct staircase-like features, indicating the presence of resonant tunnel barriers, are clearly observed in the dc I-V characteristics. Also, all samples showed a continuous change in current and zero conductivity around OV corresponding to the Coulomb blockade in the calculated dI／dV-V curve. Also, Ra-man scattering measurement showed the presence of a nano-crystalline Si structure. This result becomes a step in 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 of the future.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.113-114
• /
• 2008

Conventional furnace annealing (CFA) for activating Mg-doped p-type GaN films had been performed in pure $N_2$ ambient. All sample activated the same gas ambient. The annealing process change temperature: the first process is performed at $550^{\circ}C$ for 10 min. but, the first process is the same bulk. From second to five process increase activation temperature to change $50^{\circ}C$ and annealing time keeping for 10 min. It is found that the samples characteristic measure hall measurement. Similar results were also evidenced by photoluminescence (PL) measurement.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.29 no.11
• /
• pp.685-689
• /
• 2016

Synthesis of the fluorescent Au nanoclusters is reported. The Au nanoclusters were synthesized via reduction of gold ions in reverse micelles with mild reducing agents. The Au nanoclusters show a bright red emission at 640 nm. The fluorescent Au nanoclusters attract great interest for sensor, electronic device and bio-imaging applications because of ultra-small size, high chemical stablity and bright emission. We believe that the fluorescent Au nanoclusters can have optoelectronic applications such as optical down conversion phosphors.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.31A no.12
• /
• 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.