• Title/Summary/Keyword: GaN nanoparticles

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Synthesis and characterization of GaN nanoparticles by pulsed laser deposition (펄스레이저증착법에 의한 GaN 나노입자의 합성 및 특성분석)

  • ;;;Koshizaki Naoto
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.13 no.2
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    • pp.79-82
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    • 2003
  • GaN nanoparticles were synthesized by the pulsed laser deposition (PLD) process on $SiO_2$substrate after irradiating the surface of the GaN sintered pellet by the ArF (193 nm) excimer laser. At this moment Ar gas pressure of 100 Pa, 50 Pa, 10 Pa and 1 Pa were applied during the ablation process and laser power of 100 mJ and 200 mJ were also applied. The synthesized fan nanoparticles were characterized by XRD, SEM, TEM, XPS and optical absorption spectra. The synthesized GaN nanoparticles had the crystallite sizes of 20~30 nm, and besides, GaN nanoparticles synthesized under low Ar gas pressure compared to the others corresponded with stoichiometry, and the optical band edge of the GaN nanoparticles was blueshifted.

Gallium nitride nanoparticle synthesis using nonthermal plasma with gallium vapor

  • You, K.H.;Kim, J.H.;You, S.J.;Lee, H.C.;Ruh, H.;Seong, D.J.
    • Current Applied Physics
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    • v.18 no.12
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    • pp.1553-1557
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    • 2018
  • Gallium nitride (GaN) nanoparticles are synthesized by the gallium particle trapping effect in a $N_2$ nonthermal plasma with metallic Ga vapor. A proposed method has an advantage of synthesized GaN nanoparticle purity because the gallium vapor from the inductively heated tungsten boat does not contain any impurity source. The synthesized particle size can be controlled by the amount of Ga vapor, which is adjusted using the plasma emission ratio of nitrogen to gallium, owing to the particle trapping effect. The synthesized nanoparticles are investigated by electron microscopy studies. High-resolution transmission electron microscopy (HRTEM) studies confirm that the synthesized GaN nanoparticles (10-40 nm) crystallize in a single-phase wurtzite structure. Room-temperature photoluminescence (PL) measurements indicate the band-edge emission of GaN at around 378 nm without yellow emission, which implies that the synthesized GaN nanoparticles have high crystallinity.

Synthesis of $\beta$-$Ga_2$$O_3 Nanobelts and Nanoparticles from Mechanically Ground GaN Powders with Different Thermal Annealing Atmospheres (기계적으로 연마한 GaN 분말로부터 열처리 분위기를 달리한 $\beta$-$Ga_2$$O_3 나노벨트 및 나노입자의 합성)

  • Kim, Byung-Cheul;Sun, Kyu-Tae;Park, Kwang-Soo;Im, Ki-Joo;Noh, Tae-Yong;Nahm, Sahn;Sung, Man-Young;Kim, Sang-Sig
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.12
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    • pp.965-971
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    • 2001
  • $\beta$-Ga$_2$O$_3$ nanobelts and nanoparticles were synthesized from mechanically ground GaN powders with thermal annealing in a nitrogen atmosphere and an oxygen atmosphere, respectively. The study of field emission scanning electron microscopy (FESEM) on the microstructures of nanomaterials revealed that the nanobelts synthesized in the nitrogen atmosphere are with the range of 20~1000nm width and 10 ~100nm thickness, and that nanomaterials are nanoparticles with 20~50nm radius obtained by thermal annealing in an oxygen atmosphere. The crystal structure of the $\beta$-Ga$_2$O$_3$ nanobelts and nanoparticles was in this study investigated by X-ray diffractometer (XRD) and high-resolution transmission electron microscope (HRTEM). The formation processes of the nanobelts and nanoparticles will be discussed in this paper.

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Improved Stability of GaN-based Hydrogen Sensor with SnO2 Nanoparticles/Pd Catalyst Layer Using UV Illumination (자외선 조사를 이용한 SnO2 나노입자/Pd 촉매층을 갖는 GaN 기반 수소 센서의 안정성 개선 연구)

  • Won-Tae Choi;Hee-Jae Oh;Jung-Jin Kim;Ho-Young Cha
    • Transactions on Semiconductor Engineering
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    • v.1 no.1
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    • pp.9-13
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    • 2023
  • An AlGaN/GaN heterojunction-based hydrogen sensor with SnO2 nanoparticles/Pd catalyst layer was fabricated for room-temperature hydrogen detection. The fabricated sensor exhibited unstable drift in standby current when it was operated at room temperature. The instability in the sensing signal was dramatically improved when the sensor was operated under UV illumination.

${\beta}-Ga_2O_3$ Nanomaterials Synthesized from Mechanically Ground GaN Powders by a Thermal Annealing (기계적으로 연마한 GaN 분말로부터 열처리로 합성된 ${\beta}-Ga_2O_3$ 나노물질)

  • Park, Kwang-Soo;Sun, Kyu-Tae;In, Ki-Joo;Sung, Man-Young;Kim, Sang-Sig
    • 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).

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The study on the synthesise of Ga$_2$O$_3$ nanomaterials (Ga$_2$O$_3$ 나노물질 합성에 관한 연구)

  • 이종수;박광수;노태용;성만영;김상식
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07a
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    • pp.13-17
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    • 2002
  • Ga$_2$O$_3$ nanomaterials were synthesized from mechanically ground GaN powders with thermal annealing Ga$_2$O$_3$ nanobelts were farmed in a nitrogen atmosphere, while Ga$_2$O$_3$ nanoparticles were formed inan oxygen atmosphere. The structural properties of the Ga$_2$O$_3$ nanomaterials were investigated by X-ray diffractometer (XRD) and high-resolution transmission eleotron microscope (HRTEM). The study of field emission scanning electron microscopy (FESEM) on the microstructures of nanomaterials revealed that the nanobelts are with the range of about 10∼200nm width and 10∼50nm thickness, and that nanoparticles are with the range of about 20∼50nm radius. On the basis of XRD and HRTEM data, we determined that the nanobelts grow toward a direction perpendicular to the (010) lattice plane and that they are enclosed by facets of the (10T) and (101) lattice planes. The formation of the nanobelts may be described by the vapor-solid(VS) mechanism, and the supersaturation device of gaseous phase may play an important role in the formation of Ga$_2$O$_3$ nanomaterials.

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Synthesis and Optical Property of (GaN)1-x(ZnO)x Nanoparticles Using an Ultrasonic Spray Pyrolysis Process and Subsequent Chemical Transformation (초음파 분무 열분해와 화학적 변환 공정을 이용한 (GaN)1-x(ZnO)x 나노입자의 합성과 광학적 성질)

  • Kim, Jeong Hyun;Ryu, Cheol-Hui;Ji, Myungjun;Choi, Yomin;Lee, Young-In
    • Journal of Powder Materials
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    • v.28 no.2
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    • pp.143-149
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    • 2021
  • In this study, (GaN)1-x(ZnO)x solid solution nanoparticles with a high zinc content are prepared by ultrasonic spray pyrolysis and subsequent nitridation. The structure and morphology of the samples are investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The characterization results show a phase transition from the Zn and Ga-based oxides (ZnO or ZnGa2O4) to a (GaN)1-x(ZnO)x solid solution under an NH3 atmosphere. The effect of the precursor solution concentration and nitridation temperature on the final products are systematically investigated to obtain (GaN)1-x(ZnO)x nanoparticles with a high Zn concentration. It is confirmed that the powder synthesized from the solution in which the ratio of Zn and Ga was set to 0.8:0.2, as the initial precursor composition was composed of about 0.8-mole fraction of Zn, similar to the initially set one, through nitriding treatment at 700℃. Besides, the synthesized nanoparticles exhibited the typical XRD pattern of (GaN)1-x(ZnO)x, and a strong absorption of visible light with a bandgap energy of approximately 2.78 eV, confirming their potential use as a hydrogen production photocatalyst.

Influence of Charge Transport of Pt-CdSe-Pt Nanodumbbells and Pt Nanoparticles/GaN on Catalytic Activity of CO Oxidation

  • Kim, Sun Mi;Lee, Seon Joo;Kim, Seunghyun;Kwon, Sangku;Yee, Kiju;Song, Hyunjoon;Somorjai, Gabor A.;Park, Jeong Young
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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    • pp.164-164
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    • 2013
  • Among multicomponent nanostructures, hybrid nanocatalysts consisting of metal nanoparticle-semiconductor junctions offer an interesting platform to study the role of metal-oxide interfaces and hot electron flows in heterogeneous catalysis. In this study, we report that hot carriers generated upon photon absorption significantly impact the catalytic activity of CO oxidation. We found that Pt-CdSe-Pt nanodumbbells exhibited a higher turnover frequency by a factor of two during irradiation by light with energy higher than the bandgap of CdSe, while the turnover rate on bare Pt nanoparticles didn't depend on light irradiation. We also found that Pt nanoparticles deposited on a GaN substrate under light irradiation exhibit changes in catalytic activity of CO oxidation that depends on the type of doping of the GaN. We suppose that hot electrons are generated upon the absorption of photons by the semiconducting nanorods or substrates, whereafter the hot electrons are injected into the Pt nanoparticles, resulting in the change in catalytic activity. We discuss the possible mechanism for how hot carrier flows generated during light irradiation affect the catalytic activity of CO oxidation.

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Emission and Structural Properties of Titanium Oxide Nanoparticles-coated a-plane (11-20) GaN by Spin Coating Method

  • Kim, Ji-Hoon;Son, Ji-Su;Baik, Kwang-Hyeon;Park, Jung-Ho;Hwang, Sung-Min
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.146-146
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    • 2011
  • The blue light emitting diode (LED) structure based on non-polar a-plane (11-20) GaN which was coated TiO2 nanoparticles using spin coating method was grown on r-plane (1-102) sapphire substrates to improve light extraction efficiency. We report on the emission and structural properties with temperature dependence of photoluminescence (PL) and x-ray rocking curves (XRC). From PL results at 13 K of undoped GaN samples, basal plane stacking fault (BSF) and near band edge (NBE) emission peak were observed at 3.434 eV and 3.484 eV, respectively. We also found the temperature-induced band-gap shrinkage, which was fitted well with empirical Varshini's equation. The PL intensity of TiO2 nanoparticles ?coated multiple quantum well (MQW) sample is decayed slower than that of no coating sample with increasing temperature. The anisotrophic strain and azimuth angle dependence in the films were shown from XRC results. The full width at half maximum (FWHM) along the GaN [11-20] and [1-100] directions were 564.9 arcsec and 490.8 arcsec, respectively. A small deviation of FWHM values at in-plane direction is attributed to uniform in-plane strain.

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The structure of $Ga_2O_3$ nanomaterials synthesized by the GaN single crystal (GaN 단결정에 의해 제조된 $Ga_2O_3$ 나노물질의 구조)

  • 박상언;조채룡;김종필;정세영
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2003.11a
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    • pp.120-120
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    • 2003
  • The metallic oxide nanomaterials including ZnO, Ga$_2$O$_3$, TiO$_2$, and SnO$_2$ have been synthesized by a number of methods including laser ablation, arc discharge, thermal annealing procedure, catalytic growth processes, and vapor transport. We have been interested in preparing the nanomaterials of Ga$_2$O$_3$, which is a wide band gap semiconductor (E$_{g}$ =4.9 eV) and used as insulating oxide layer for all gallium-based semiconductor. Ga$_2$O$_3$ is stable at high temperature and a transparent oxide, which has potential application in optoelectronic devices. The Ga$_2$O$_3$ nanoparticles and nanobelts were produced using GaN single crystals, which were grown by flux method inside SUS$^{TM}$ cell using a Na flux and exhibit plate-like morphologies with 4 ~ 5 mm in size. In these experiments, the conventional electric furnace was used. GaN single crystals were pulverized in form of powder for the growth of Ga$_2$O$_3$ nanomaterials. The structure, morphology and composition of the products were studied mainly by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HRTEM).).

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