• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.2
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• pp.158-162
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• 2009

$Zn_2SiO_4$:Mn green phosphors doped with Ga for PDP were synthesized by solid state reaction method. Photoluminescence measurements showed a new emission peak at around 600 nm for $Zn_2SiO_4$:Mn phosphors doped with Ga. Also, the luminescent color with doping $Ga^{3+}$ in the $Zn_2SiO_4$:Mn phosphors changed to green from yellowish green. Consequently, the new peak and charge of the luminescent color in the $Zn_2SiO_4$:Mn, Ga phosphors were attributed to $^2E{\rightarrow}^6A_2$ transition of $Mn^{4+}$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.2
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• pp.155-160
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• 2020

Ga₂O₃/n-type 4H-SiC heterojunction diodes were fabricated by RF magnetron sputtering. The optical properties of Ga₂O₃ and electrical properties of diodes were investigated. I-V characteristics were compared with simulation data from the Atlas software. The band gap of Ga₂O₃ was changed from 5.01 eV to 4.88 eV through oxygen annealing. The doping concentration of Ga₂O₃ was extracted from C-V characteristics. The annealed oxygen exhibited twice higher doping concentration. The annealed diodes showed improved turn-on voltage (0.99 V) and lower leakage current (3 pA). Furthermore, the oxygen-annealed diodes exhibited a temperature cross-point when temperature increased, and its ideality factor was lower than that of as-grown diodes.

• Proceedings of the KIEE Conference
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• 2001.11a
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• pp.158-160
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• 2001

${\beta}-Ga_2O_3$ nanobelts and nanoparticles were synthesized by a thermal annealing of as-milled GaN powders at $930^{\circ}C$ in nitrogen and oxygen atmosphere. respectively. The width of the nanobelts are $20\;nm{\sim}1000\;nm$. the thickness of the nanobelts are 100 nm. A bundle of the nanobelts is several centimeters in length. The lattice structure of these nanobelts and nanoparticles was identified to be a monoclinic ${\beta}-Ga_2O_3$ by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.12
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• pp.984-989
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• 2012

We have investigated the structural, electrical and optical properties of Ga-doped ZnO (GZO) thin films prepared by RF magnetron sputtering with laboratory-made ZnO targets containing 1, 3, 5, 7 wt% of $Ga_2O_3$ powder as a doping source. The GZO thin films show the typical crystallographic orientation with c-axis regardless of $Ga_2O_3$ content in the targets. The $3,000{\AA}$ thick GZO thin films with the lowest resistivity of $7{\times}10^{-4}{\Omega}{\cdot}cm$ are obtained by using the GZO ($Ga_2O_3$= 5 wt%) target. Optical transmittance of all films shows higher than 80% at the visible region. The optical energy band gap for GZO films increases as the carrier concentration ($n_e$) in the film increases.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.1
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• pp.40-44
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• 2022

Wet etching of α-Ga₂O₃ epitaxy film was performed using a 35 % hydrochloric (HCl) acid solution. As the temperature of the 35 % HCl solution increased, the α-Ga₂O₃ etch rate increased, and the etch rate of 119.6 nm/min was obtained at 75℃, the highest temperature examined in this work. The activation energy for etch reaction was determined to be 0.776 eV, and this suggests that the wet etching of α-Ga₂O₃ in the 35 % HCl solution was dominated by the reaction-limited mechanism. AFM analysis showed that the surface roughness of the etched surface increased as the temperature of the etchant solution increased.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.201-201
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• 2010

본 연구에서는 RF magnetron co-sputtering을 이용하여 Zn-O-Ga 구성비에 따른 광투과도 및 전기적 특성을 연구하였다. 타겟으로 ZnO 및 $Ga_2O_3$ 소결체를 이용하였으며, 두 개의 RF magnetron sputter의 RF power를 동시에 조절하여 타겟의 구성비를 조절하였으며, 기판과 타겟의 거리를 25 mm~75 mm 범위 내에 조절하여 거리에 따른 Zn-O-Ga 박막의 광투과 특성 및 전기적 특성을 관찰하였다. $Ga_2O_3$ 소결체의 magnetron sputter의 RF power를 30 watt에서 100 watt로 증가함에 따라 박막내의 Ga 성분은 0.5%에서 7.4%로 증가하였으며 Zn 성분은 46.3%에서 40.9%로 O성분은 53.2%에서 51.6%로 각각 줄어들었다. 이에 따라 ZnO의 우선방위 (002) 결정각($2{\theta}$)은 34.24에서 33.87로 줄어들었으며, 이동도 $5.5\;cm^2/Vs$ 에서 $1.99\;cm^2/Vs$ 정도로 감소하는 경향을 보였다. 광투과도는 가시광선 영역에서 85% 이상 보였으며, carrier 밀도는 $0.5\;{\sim}\;4.0^*10^{20}/cm^3$로 증가함에 따라 이동도는 $1.5{\sim}5.5\;cm^2/Vs$로 투명전도막의 특성을 보였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.68-71
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• 1996

In the study, the thermal and optical properties of SiO$_2$-PbO-K$_2$O-Al$_2$O$_3$ g1asses were investigated. According to Ga$_2$O$_3$ addictions, the properties of bulk glass, transition temperature and softening temperature were increased, whereas thermal expansion coefficient was decreased; In the optical properties, refractive index was increased, and IR cut-off wavelength was enlarged from 4.64$\mu\textrm{m}$ to 5.22$\mu\textrm{m}$. But, the optical loss of fiber was decreased.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.95-96
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• 2007

DC magnetron sputtering 법으로 다양한 $Ga_2O_3$함량비( $2.27{\sim}$ 10.81 wt%)를 가진 고밀도 GZO 소결타겟을 사용하여 GZO박막을 증착한 후 도핑농도에 따른 광학적 특성과 전기적 특성을 조사하였다. GZO($Ga_2O_3$: 6.65 wt%)타겟을 사용하여 기판온도 $300^{\circ}C$에서 증착한 GZO박막은 상대적으로 낮은 비저항($5.1{\times}10^{-4}$ ${\Omega}cm$)과 85% 이상의 높은 투과율을 보였다. 또한 타겟의 $Ga_2O_3$함량이 6.65 wt%일때 광학적 밴드갭 에너지는 3.61 eV로 비교적 큰 흡수계수의 변화를 보였으며 그 이상의 $Ga_2O_3$농도에서는 밴드갭 에너지가 감소하는 경향을 보였다.

• Journal of the Korean Magnetics Society
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• v.16 no.2
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• pp.144-148
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• 2006

$CoGa_{0.1}Fe_{1.9}O_4$ nanoparticles have been prepared by a sol-gel method. The structural and magnetic properties have been investigated by XRD, SEM, VSM and $M\ddot{o}ssbauer$ spectroscopy. $CoGa_{0.1}Fe_{1.9}O_4$ powder that was annealed at $250^{\circ}C$ has spinel structure and behaved superparamagnetically. The estimated size of superparammagnetic $CoGa_{0.1}Fe_{1.9}O_4$ nanoparticle is around 10 nm. The hyperfine fields at 4.2 K f3r the A and B patterns were found to be 518 and 486 kOe, respectively. The blocking temperature $(T_B)$ of superparammagnetic $CoGa_{0.1}Fe_{1.9}O_4$ nanoparticle is about 250 K. The magnetic anisotropy constant of $CoGa_{0.1}Fe_{1.9}O_4$ nanoparticle was calculated to be $3.0X10^5\;ergs/cm^3$. $CoGa_{0.1}Fe_{1.9}O_4$ nanoparticle was annealed at $250^{\circ}C$ will be used to candidate for biomedicine applications as magnetic carriers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.334-337
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• 2002

In this study, the microstructure, dielectric and piezoelectric properties of $0.15Pb(Ni_{1/3}Nb_{2/3})O_3-0.85(PbZr_{0.5}Ti_{0.5})O_3$(0.15PNN-0.85PZT) ceramics having compositions near the morphotropic phase boundary(MPB) was investigated with respect to the variation of $Y_2O_3$ and $Ga_2O_3$ addition amount. The dielectric properties increased and piezoelectric properties decreased with increasing the amount of $Ga_2O_3$. The solubility limit of $Y_2O_3$ is 0.5mol% in this system. The electro-mechanical coupling factor$(K_p)$ and dielectric constant(${\varepsilon}_r$) were 58.6% and 1755 when the amount of $Y_2O_3$ are 0.5mol%.