• Bulletin of the Korean Chemical Society
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• 제22권9호
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• pp.975-978
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• 2001

A novel poly[9,10-diphenylanthracene-4',4"-ylenevinylene-3,6-(N-2-ethyl hexyl)carbazole] containing alternate diphenylanthracene and carbazole unit was synthesized by the Wittig reaction. The obtained polymer was soluble in common organic solvents and thermally stable up to 380 $^{\circ}C.$ The polymer gives rise to bright blue fluorescence both in solution and in thin solid films. The light emitted from the device (ITO/polymer/Al) was greenish-blue in color and clearly visible in daylight.

• Journal of Advanced Marine Engineering and Technology
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• 제25권6호
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• pp.1272-1280
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• 2001

SrS:Ce thin films for blue EL devices were prepared by Hot Wall Method and their crystallographic and optical characteristics were investigated by various methods. Deposition rates were increased with SrS cell temperature, but the rates were independent on substrate temperature and sulfur pressure. The optical and crystallographic characteristics were strongly affected by deposition rates. The band gap energies obtained by optical transmission spectra and Full Width at Half Maximum of (200) plane in X-ray diffraction patterns were found at 4.5-4.6eV and $0.22~0.26^{\circ}$, respectively. The photoluminescence from SrS:Ce thin tiles showed a greenish blue omission peaked at 470 and 540nm.

• Journal of Advanced Marine Engineering and Technology
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• 제30권4호
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• pp.514-519
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• 2006

SrS:Cu, Cl thin films have been grown by the hot wall technique with S furnace placed on the outside of the growth chamber in order to investigate the crystallographic and optical characteristics. The films have a good crystallinity independent of CuCl wall temperature and PL characteristics showed a peak assigned by the transition form $3d^94s^1\;(^3Eg)$ to $3d^{10}\;(^1A_{1g})$ of $Cu^+$ center. It has also been found that. from the PLE spectra, $Cu^+$ luminescent centers are doped in the host materials. The EL emission from SrS:Cu-based device showed a greenish-blue but shifted to short wavelength compared to SrS:Ce-based EL. The device was obtained the maximum luminance of $110cd/m^2$ and the maximum luminous efficiency of $0.1\;lm/W$ at $V_{40}$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.50-50
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• 2008

ZnO has been extensively studied for optoelectronic applications such as blue and ultraviolet (UV) light emitters and detectors, because it has a wide band gap (3.37 eV) anda large exciton binding energy of ~60 meV over GaN (~26 meV). However, the fabrication of the light emitting devices using ZnO homojunctions is suffered from the lack of reproducibility of the p-type ZnO with high hall concentration and mobility. Thus, the ZnO-based p-n heterojunction light emitting diode (LED) using p-Si and p-GaN would be expected to exhibit stable device performance compared to the homojunction LED. The n-ZnO/p-GaN heterostructure is a good candidate for ZnO-based heterojunction LEDs because of their similar physical properties and the reproducibleavailability of p-type GaN. Especially, the reduced lattice mismatch (~1.8 %) and similar crystal structure result in the advantage of acquiring high performance LED devices with low defect density. However, the electroluminescence (EL) of the device using n-ZnO/p-GaN heterojunctions shows the blue and greenish emissions, which are attributed to the emission from the p-GaN and deep-level defects. In this work, the n-ZnO:Ga/p-GaN:Mg heterojunction light emitting diodes (LEDs) were fabricated at different growth temperatures and carrier concentrations in the n-type region. The effects of the growth temperature and carrier concentration on the electrical and emission properties were investigated. The I-V and the EL results showed that the device performance of the heterostructure LEDs, such as turn-on voltage and true ultraviolet emission, developed through the insertion of a thin intrinsic layer between n-ZnO:Ga and p-GaN:Mg. This observation was attributed to a lowering of the energy barriers for the supply of electrons and holes into intrinsic ZnO, and recombination in the intrinsic ZnO with the absence of deep level emission.