• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.78-79
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• 2009

본 연구에서는 ZnO계 투명전극 소재를 이용하여 RFID 태그 안테나에 적용 가능성 여부를 확인하였다. Si 기판위에 RF 스퍼터링 공정에 의해 Ga-doped ZnO 투명 마이크로스트립 스파이혈 안테나를 $2{\mu}m$를 증착하여 구현하고 그 전기적 특성을 측정하였다. HFSS 전자계 시뮬레이터를 사용하여 13.56MHz HF 주파수 대역에서 태그 안테나로서의 가능성을 검증한 후 Ga-doped ZnO 타겟을 사용한 RF 스퍼터링 공정에 의하여 스파이럴 안테나 패턴을 구현하였다. 마이크로스트립 선폭 및 선 간격을 $50\sim200{\mu}m$때 영역에서 조절하면서 안테나 패턴을 설계하였다. S 파라메터, 자기공진주파수 및 Q값을 시뮬레이션으로부터 도출하였다. Al $2{\mu}m$ 증착한 시편에 비하여 약 -10dB 정도의 이득저하가 발생하였으나 리더-태그를 밀착시킨 조건에서 1.7V (13.56MHz) 전압검출이 가능하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.831-833
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• 2008

150 nm thick Ga-doped ZnO thin film, which was deposited by a sputtering process, was wet-chemically etched by using various organic acids such as oxalic, citric and formic acid. Wet etch parameters including etchant concentration and temperature are investigated for each etchant, and their effects on the etch rate and the feature of edge line are compared.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.4
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• pp.354-358
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• 2004

In this thesis, an analytical model for Ⅰ-Ⅴ characteristics of an n-AlGaAs/GaAs Delta doped HEMT is proposed. 2-dimensional electron gas density, and conduction band edge profile are calculated from a self-consistent iterative solution of the Poisson equation. Parameters, e.g., the saturation velocity, 2-dimensional electron gas concentration, thickness of the doped and undoped layer(AlGaAs, GaAs, spacer etc.,) are in good agreement with the independent calculations.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.9
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• pp.776-779
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• 2007

In this study we present the effect of annealing temperatures on the structural, electrical and optical characteristics of Ga-doped ZnO (GZO) films. GZO target is deposited on coming 7059 glass substrates by DC sputtering. and then GZO films are annealed at temperatures of 400, 500, $600^{\circ}C$ in air ambient for 20 min. in this case of as-grown film, it shows the resistivity of $6{\times}10^{-1}{\Omega}{\cdot}cm$ and transmittance under 85%, whereas the electrical and optical properties of film annealed at $500^{\circ}C$ are enhanced up to $1.9{\times}10^{-3}{\Omega}{\cdot}cm$ and 90%, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.313-314
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• 2007

Ga-doped ZnO(GZO) multilayer coatings were prepared on glass by DC sputtering. Optimization of the deposition conditions of both AZO and Au layers were performed for better electrical and optical characteristics. The properties of multilayer were affected by the deposition process of both GZO and Au layers. The best multilayer coating exhibits low resistivity of $2.72{\times}10^{-3}\;{\Omega}-cm$ and transmittance of 77%. From these results, we can confirm a possibility of the application as transparent conductive electrodes.

• Korean Journal of Optics and Photonics
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• v.8 no.3
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• pp.213-217
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• 1997

We have measured photoluminescence (PL) and time-resolved PL in doped-GaAs. As increasing doping concentration, the PL spectra of n-type GaAs shift to higher energies while the PL spectra of p-type GaAs shift to lower energies than the bandgap of the undoped GaAs. The contribution of the Burstein-Moss effect overrules the band-gap narrowing in n-type GaAs, contrary to p-type GaAs. The PL rise time and decay time become shorter as increasing doping concentration. The PL rise and decay time in doped-GaAs depend on the type of majority carriers and their concentrations, which imply that the carrier-carrier interaction plays an important role in the energy relaxation processes.

• Journal of Ceramic Processing Research
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• v.13 no.spc1
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• pp.128-131
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• 2012

The selective area growth light emitting diode on GaN substrate was grown using mixed-source HVPE method with multi-sliding boat system. The GaN substrate was grown using mixed-source HVPE system. Te-doped AlGaN/AlGaN/Mg-doped AlGaN/Mg-doped GaN multi-layers were grown on the GaN substrate. The appearance of epi-layers and the thickness of the DH was evaluated by SEM measurement. The DH metallization was performed by e-beam evaporator. n-type metal and p-type metal were evaporated Ti/Al and Ni/Au, respectively. At the I-V measurement, the turn-on voltage is 3 V and the differential resistance is 13 Ω. It was found that the SAG-LED grown on GaN substrate using mixed-source HVPE method with multi-sliding boat system could be applied for developing high quality LEDs.

• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.246-246
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• 2005

• Ceramist
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• v.10 no.3
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• pp.28-33
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• 2007

The structural and optical properties of Ni-doped transparent glass-ceramics are reviewed. The quantum efficiencies of ceramics were examined to explore suitable crystalline phase for Ni-doping in glass-ceramics. Inverse spinel $LiGa_5O_8$ have the quantum efficiency of almost 100 % at room temperature. Transparent glass ceramics containing $LiGa_5O_8$ was successfully synthesized by heat treatment of $Li_2O-Ga_2-O_3-SiO_2-NiO$ glass. Most of $Ni^{2+}$ ions in glass-ceramic were incorporated into $LiGa_5O_8$ nanocrystals. The near-infrared emission covering from the O-band to L-band (1260-1625 nm) was observed from the Ni-doped $Li_2O-Ga_2O_3-SiO_2$ glass-ceramic though it was not observed from the as-cast glass. The lifetime of the emission was about $580\;{\mu}sec$ even at 300K. The emission quantum efficiency was evaluated as about 10 % that is enough high for practical usage as gain media of optical fiber amplifiers. The figure of merit (the product of the stimulated emission cross section and lifetime) was as high as that of rare-earth-doped glasses. The broad bandwidth, high quantum efficiency and high figure of merit show that transparent glass-ceramics containing $Ni^{2+}:LiGa_5O_8$ nanocrystals are promising candidates as novel ultra-broadband gain media.

• Journal of the Korean Vacuum Society
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• v.10 no.1
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• pp.67-71
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• 2001

Optical investigation on Zn-doped InGaN grown by MOCVD was performed by using the photoluminescence. Two different spectra related to Zn-acceptor-like centers occurred at room temperature, with broad emissions peaking at 2.81, and 2.60 eV, Specially, emissions interacted with phonon were observed at 2.81 eV where phonon energy was 92.5 meV From temperature dependent blue-band emissions of InGaN, we observe that the intensity in high energy region was quickly decreased more than that in low energy region with increased temperature, and the peak position at 2.81 eV was blue shift of about 18 meV, The blue-band emmissions would be originated from the transition related to the localized Zn complex centers.