• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.142-142
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• 2009

Zinc Oxide (ZnO)는 wurtzite 결정구조를 가지고 있으며, 밴드갭 에너지가 약 3.4eV인 산화물 반도체 이다. GaN가 도핑된 ZnO 박막을 Pulsed Laser Deposition (PLD) 법을 이용하여 사파이어 기판과 실리콘 기판에 각각 증착하였다. $500^{\circ}C$의 증착온도에서 1at%~10at%까지의 GaN 도핑농도에 따른 ZnO 박막의 결정성, 성분 분석을 비롯한 전기적 특성을 조사하였다. 첨가된 GaN의 농도에 따라 ZnO 박막의 결정성이 변화하였으며, 농도 변화에 상관없이 ZnO(002) 방향으로 성장함을 알 수 있었다. 또한 실리콘 기판에 증착한 GaN-doped ZnO 박막은 5at%에서 $9.3\;{\times}\;10-3{\Omega}cm$, 10at%에서 $9.2\;{\times}\;10-3{\Omega}cm$의 비저항 값을 가지며 각각 p-type 특성을 나타내었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.391.2-391.2
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• 2014

Solution-processible hybrid bipolar field effect transistors (HBFETs) with balanced hole and electron mobilities were fabricated using a combination of the organic p-type poly (3-hexylthiophene) (P3HT) layer and inorganic n-type ZnO material. The hole and electron mobilities were first optimized in single layer devices by using acetonitrile as a solvent additive to process the P3HT and annealing to process the ZnO layer. The highest hole mobility of the P3HT-only-devices with 5% acetonitrile was 0.15 cm2V-1s-1, while the largest electron mobility was observed in the ZnO-only-devices annealed at $200^{\circ}C$ and found to be $7.2{\times}10-2cm2V-1s-1$. The inorganic-organic HBFETs consisting of P3HT with 5% acetonitrile and ZnO layer annealed at $200^{\circ}C$ exhibited balanced hole and electron mobilities of $4.0{\times}10-2$ and $3.9{\times}10-2cm2V-1s-1$, respectively. The effect on surface morphology and crystallinity by adding acetonitrile and thermal annealing were investigated through X-ray diffraction and atomic force microscopy (AFM). Our findings indicate that techniques demonstrated herein are of great utility in improving the performance of inorganic-organic hybrid devices

• 한국재료학회지
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• 제26권6호
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• pp.347-352
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• 2016

ZnO with wurtzite structure has a wide band gap of 3.37 eV. Because ZnO has a direct band gap and a large exciton binding energy, it has higher optical efficiency and thermal stability than the GaN material of blue light emitting devices. To fabricate ZnO devices with optical and thermal advantages, n-type and p-type doping are needed. Many research groups have devoted themselves to fabricating stable p-type ZnO. In this study, $As^+$ ion was implanted using an ion implanter to fabricate p-type ZnO. After the ion implant, rapid thermal annealing (RTA) was conducted to activate the arsenic dopants. First, the structural and optical properties of the ZnO thin films were investigated for as-grown, as-implanted, and annealed ZnO using FE-SEM, XRD, and PL, respectively. Then, the structural, optical, and electrical properties of the ZnO thin films, depending on the As ion dose variation and the RTA temperatures, were analyzed using the same methods. In our experiment, p-type ZnO thin films with a hole concentration of $1.263{\times}10^{18}cm^{-3}$ were obtained when the dose of $5{\times}10^{14}$ As $ions/cm^2$ was implanted and the RTA was conducted at $850^{\circ}C$ for 1 min.

• 대한화학회지
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• 제45권3호
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• pp.251-255
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• 2001

LiZnBO3 화합물의 결정구조에 대한 실험은 단결정 X-ray 회절 분광법에 의해서 수행되었다. 화합물의 단위포 격자상수는 $a=5.0915(9)\AA$, $b=5.059(1)\AAc=6.156(1)\AA$, $V=120.6(1)\AA3$, $\alpha=65.81(1)^{\circ}$, $\beta=65.56(1)^{\circ}$와$\gamma=59.77(1)^{\circ}$이고, 공간 그룹은 P1(Z=2)이다. 화합물의 구조는 704개의 독특한 반사 복사선들에 의해서 결정되었으며, 최종, R값은 0.039이고, wR값은 0.056이다. 이 화합물은 평면삼각형의 BO3그룹과 찌그러진 사면체 구조의 Li04와 ZnO4그룹으로 구성되었으며, Li 원자와 Zn 원자들이 불연속적으로 배열되었다. 번갈아 가면서 불연속적으로 배열된 원자의 충진율은 각각 원자들, Li1, Li2, Zn1 와 Zn2 격자위치에서 약 50%이었다.

• 한국전기전자재료학회논문지
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• 제29권8호
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• pp.489-493
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• 2016

In this study, the effect of vanadium oxide ($V_2O_5$) content and pre-sintering atmosphere on sealing property of glass frit that consisted of $V_2O_5-BaO-ZnO-P_2O_5-TeO_2-CuO-Fe_2O_3-SeO_2$ was investigated by XPS (X-ray photoelectron spectroscopy). The content of V2O5 was changed to 15, 30, and 45 mol%, and the pre-sintering was carried out in air and $N_2$ condition, respectively. XPS analysis conducted before and after laser irradiation with identical sample. Before laser treatment, glass frits that were pre-sintered at air condition showed both $V^{4+}$ and $V^{5+}$, but the valence state was changed to $V^{5+}$ after laser irradiation when the glass frits contained 30 and 45 mol% $V_2O_5$; this change led to non-adhesive property. On the other hand, glass frits that were pre-sintered at $N_2$ condition exhibited only $V^{4+}$ and it showed fine adhesion irrespective of the $V_2O_5$ content. As a result, the existence of $V^{4+}$ seems to be a major factor for controlling the adhesive property of glass frit for laser sealing.

• 센서학회지
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• 제5권6호
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• pp.68-73
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• 1996

고주파 마그네트론 스펏터링법을 이용하여 유리 및 (012)면인 사파이어 기판위에 ZnO박막을 제조하였다. 유리기판위에는 (002)면을 갖는 ZnO 다결정박막이 제조되었으며, (012)면인 사파이어 기판위에는 (110)면인 ZnO에 피택셜 박막이 제조되었다. 유리 및 사파이어 기판위에 제조된 ZnO박막의 표면탄성파 특성을 조사하였다. 유리 및 사파이어 기판에 대한 중심주파수에서의 전파속도는 각각 2680 m/sec 및 5980 m/sec였으며, 기본모드에서 구한 결합계수는 각각 0.98 % 및 1.44 %였다.

• 한국재료학회지
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• 제19권8호
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• pp.443-446
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• 2009

This study develops a highly transparent ohmic contact scheme using indium oxide doped ZnO (IZO) as a current spreading layer for p-GaN in order to increase the optical output power of nitride-based lightemitting diodes (LEDs). IZO based contact layers of IZO, Ni/IZO, and NiO/IZO were prepared by e-beam evaporation, followed by a post-deposition annealing. The transmittances of the IZO based contact layers were in excess of 80% throughout the visible region of the spectrum. Specific contact resistances of $3.4\times10^{-4}$, $1.2\times10^{-4}$, $9.2\times0^{-5}$, and $3.6\times10^{-5}{\Omega}{\cdot}cm^2$ for IZO, Ni/Au, Ni/IZO, and NiO/IZO, respectively were obtained. The forward voltage and the optical output power of GaN LED with a NiO/IZO ohmic contact was 0.15 V lower and was increased by 38.9%, respectively, at a forward current of 20 mA compared to that of a standard GaN LED with an Ni/Au ohmic contact due to its high transparency, low contact resistance, and uniform current spreading.

• Nuclear Engineering and Technology
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• 제51권8호
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• pp.2005-2012
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• 2019

This work investigated the radiation attenuation characteristics of three series of tellurite glass systems with the following compositions: 30PbO-10ZnO-xTeO₂-(60-x)B₂O₃ where x = 10, 30, 40, 50 and 60 mol%, xBaO-xB₂O₃-(100-2x)TeO₂ with x = 15-40 mol% and 50ZnO-(50-x)P₂O₅-xTeO₂, where x = 0, 10, .40 mol%. The results revealed that the attenuation parameters in all the samples decrease with increase in the energy, which implied that all the samples have better interaction with gamma photons at low energies and thus higher photon attenuating efficiency. From the three systems, the samples coded as PbZnBTe60, BaBTe70 and ZnPTe40 have the lowest half value layer values and accordingly have superior photon attenuation efficacy. The maximum effective atomic number values were found for energy less than 0.1 MeV particularly near the K-edges absorption of the heavy atomic number elements such as Te, Ba and Pb. At the lowest energy, the Z_eff values are found in the range of 62.33-66.25, 49.43-50.81 and 24.99-35.83 for series 1-3 respectively. Also, we found that the density of the glass remarkably affects the photon attenuation ability of the selected glasses. The mean free path results showed that the PbO-ZnO-TeO₂-B₂O₃ glass system has better radiation shielding efficiency than the glass samples in series 2 and 3.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.456-456
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• 2013

We report the modifications in the electronic structureof ZnO thin films induced by swift heavy ion (SHI) irradiated ZnO thin films by using near edge X-ray absorption fine structure (NEXAFS) spectroscopy at O K-edge was performed at BL10D XAS-KIST beamline at Pohang Accelerator Lab (PAL). ZnO films of 250 nm thickness oriented in [200] plane deposited by RF magnetron sputtering using equal $Ar:O_2$ atmosphere and air annealed at $500^{\circ}C$ for 6 hours for stability were irradiated with 120 MeV Au and 100 MeV O beams separately with different doses ranging from $1{\times}10^{11}$ to $5{\times}10^{12}$ ions/$cm^2$. High Resolution X-ray diffraction and NEXAFS analysis indicates significant changes in the electronic structure and the SHI effect is different for Ag and O-beams. The NEXAFS measurements provide direct evidence of O 2p and Zn 3d orbital hybridization. The NEXAFS results will be presented in detail.

• 한국전기전자재료학회논문지
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• 제16권12호
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• pp.1071-1076
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• 2003

The nonlinear properties and their stability of ZPCCD- based varistors, which are composed of ZnO P $r_{6}$ $O_{ll}$ - CoO-C $r_2$ $O_3$-D $y_2$ $O_3$-based ceramics, were investigated in the D $y_2$ $O_3$ content range of 0.0∼2.0 mol%. The incorporation of D $y_2$ $O_3$ greatly affected the nonlinear properties and the best nonlinearity was obtained from 0.5 mol% D $y_2$ $O_3$ with nonlinear exponent of 66.6 and leakage current of 1.2 $\mu$A. Further addition of D $y_2$ $O_3$ deteriorated the nonlinear properties. In stability against DC accelerated aging stress state: 0.95 $V_{1mA}$/15$0^{\circ}C$/24 h, the 0.5 mol％ D $y_2$ $O_3$-doped varistor exhibited the highest stability, in which the variation rate of varistor voltage and nonlinear exponent are -1.9% and 10.5%, respectively. The remainder varistors resulted in thermal runaway due to low density of ceramics.s.s.