• Title/Summary/Keyword: Vapor phase epitaxy method

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Preparation of Zn-Doped GaN Film by HVPE Method (HVPE법에 의한 Zn-Doped GaN 박막 제조)

  • Kim, Hyang Sook;Hwang, Jin Soo;Chong, Paul Joe
    • Journal of the Korean Chemical Society
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    • v.40 no.3
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    • pp.167-172
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    • 1996
  • For the preparation of single-crystalline GaN film, heteroepitaxial growth on a sapphire substrate was carried out by halide vapor phase epitaxy(HVPE) method. The resulting GaN films showed n-type conductivity. The insulator type GaN film was made by doping with Zn(acceptor dopant), which showed emission peaks around 2.64 and 2.43 eV. The result of this study indicates that GaN can be obtained in an epitaxial structure of MIS(metal-insulator-semiconductor) junction. The observed data are regarded as fundamental in developing GaN epitaxial films for light emitting devices of hetero-structure type.

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Characteristics of selective area growth of GaN/AlGaN double heterostructure grown by hydride vapor phase epitaxy on r-plane sapphire substrate (HVPE 방법에 의해 r-plane 사파이어 기판 위의 선택 성장된 GaN/AlGaN 이종 접합구조의 특성)

  • Hong, S.H.;Jeon, H.S.;Han, Y.H.;Kim, E.J.;Lee, A.R.;Kim, K.H.;Hwang, S.L.;Ha, H.;Ahn, H.S.;Yang, M.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.19 no.1
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    • pp.6-10
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    • 2009
  • In this paper, a selective area growth (SAG) of a GaN/AlGaN double heterostructure (DH) has been performed on r-plane sapphire substrate by using the mixed-source hydride vapor phase epitaxy (HVPE) with multi-sliding boat system. The SAG-GaN/AlGaN DH consists of GaN buffer layer, Te-doped AlGaN n-cladding layer, GaN active layer, Mg-doped AlGaN p-cladding layer, and Mg-doped GaN p-capping layer. The electroluminescence (EL) characteristics show an emission peak of wavelength, 439 nm with a full width at half maximum (FWHM) of approximately 0.64 eV at 20 mA. The I-V measurements show that the turn-on voltage of the SAG-GaN/AlGaN DH is 3.4 V at room temperature. We found that the mixed-source HVPE method with a multi-sliding boat system was one of promising growth methods for III-Nitride LEDs.

Single Crystal Growing of Gallium Nitride Films on (0001), (10${\bar{1}}$2) and(11${\bar{2}}$0) Sappire ((0001), (10${\bar{1}}$2)와 (11${\bar{2}}$0) Sapphire 기판에서 Gallium Nitribe 단결정 박막의 성장)

  • 황진수;알렉산
    • Korean Journal of Crystallography
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    • v.5 no.1
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    • pp.24-32
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    • 1994
  • The study of (0001), (1120) and (1011) GAN epitaxy films grown on the (0001),(1012) and (1120) α-Al2O3 substrates have been investigated using the haliar vapor phaes epitaxy(HVPE) method in Ga/HCI/NH3/He system. XRD, RHEED and SEM are used for the study of the films struction and surface morphology. Chemical composition of the film surface is estimsted by XPS. The following orientation relationships are observed; (0001) GaN /(0001) Al2O3 (1120) GaN/ (1012) Al2O3 and (0001) and (1011) GaN/ (1120) Al2O3 in accordance with growth conditions. The (0001) GaN films grown on(0001) and (1120) a-Al2O3 substrates at higer temperature(1050℃) have shown two dimensional grownth mechanism. Form SEM and RHEED, the smoother surface morphology and better structure are observed for the (1011) GaN films grown on (1120) sapphire at higer temperature.

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Investigation of thermodynamic analysis in GaN thick films gtowth (GaN 후막 증착의 열역학적 해석에 관한 연구)

  • 박범진;박진호;신무환
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.8 no.3
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    • pp.388-395
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    • 1998
  • This paper reports on a thermodynamic analysis for the GaN thick film growth by vapor phase epitaxy method. The thermodynamic calculation was performed using a chemical stoichiometric algorism. The simulation variables include the growth temperature in a range 400~1500 K, the gas ratios $(GaCl_3)/(GaCl_3+NH_3)$ and $(N_2)/(GaCl_3+NH_3)$. The theoretical calculation predicts that the growth temperature of GaN be in the lower range of 450~750 K than the experimental results. The difference in the growth temperature between the simulation and the experiments indicates that the vapor phase epitaxy of GaN is kinetically limited, presumably, due to the high activation energy of thin film growth.

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Distance between source and substrate and growth mode control in GaN nanowires synthesis (Source와 기판 거리에 따른 GaN nanowires의 합성 mode 변화 제어)

  • Shin, T.I.;Lee, H.J.;Kang, S.M.;Yoon, D.H.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.18 no.1
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    • pp.10-14
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    • 2008
  • We synthesized GaN nanowires with high quality using the vapor phase epitaxy technique. The GaN nanowires were obtained at a temperature of $950^{\circ}C$. The Ar and $NH_3$ flow rates were 1000 sccm and 50 sccm, respectively. The shape of the GaN nanowires was confirmed through FESEM analysis. We were able to conclude that the GaN nanowires synthesized via vapor-solid (VLS) mechanism when the source was closed to the substrate. On the other side, the VS mechanism changed to vapor-liquid-solid (VLS) as the source and the substrate became more distant. Therefore, we can suggest that the large amount of Ga source from initial growth interrupt the role of catalyst on the substrate.

Characterization of In(Al)GaN layer grown by mixed-source hydride vapor phase epitaxy (혼합소스 HVPE에 의해 성장된 In(Al)GaN 층의 특성)

  • Hwang, S.L.;Kim, K.H.;Jang, K.S.;Jeon, H.S.;Choi, W.J.;Chang, J.H.;Kim, H.S.;Yang, M.;Ahn, H.S.;Bae, J.S.;Kim, S.W.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.16 no.4
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    • pp.157-161
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    • 2006
  • InGaN layers on GaN templated sapphire (0001) substrates were grown by mixed-source hydride vapor phase epitaxy (HVPE) method. In order to get InGaN layers, Ga-mixed In metal and $NH_3$ gas were used as group III and group V source materials, respectively. The InGaN material was compounded from chemical reaction between $NH_3$ and indium-gallium chloride farmed by HCl flowed over metallic In mixed with Ga. The grown layers were confirmed to be InGaN ternary crystal alloys by X-ray photoelectron spectroscopy (XPS). In concentration of the InGaN layers grown by selective area growth (SAG) method was investigated by the photoluminescence (PL) and cathodoluminescence (CL) measurements. Indium concentration was estimated to be in the range 3 %. Moreover, as a new attempt in obtaining InAlGaN layers, the growth of the thick InAlGaN layers was performed by putting small amount of Ga and Al into the In source. We found the new results that the metallic In mixed with Ga (and Al) as a group III source material could be used in the growth process of the In(Al)GaN layers by the mixed-source HVPE method.

Vapor Phase Epitaxial Growth and Properties of GaN (GaN의 기상성장과 특성)

  • 김선태;문동찬
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1996.05a
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    • pp.72-75
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    • 1996
  • A hydride vapor phase epitaxy (HVPE) method is performed to prepare the GaN thin films on c-plane sapphire substrate. The full-width at half maximum of double crystal X-ray rocking curves from 20$\mu\textrm{m}$-thick GaN was 576 arcsecond. The photoluminescence spectrum measured 10 K shows the hallow bound exciton (I$_2$) line and weak donor-acceptor peak, however, there was not observed deep donor-acceptor pair recombination indicate the GaN crystals prepared in this study are of high purity and high crystalline quality. The GaN layer is n-type conducting with electron mobility of 72 $\textrm{cm}^2$/V$.$sec and with carrier concentration of 6 x 10$\^$18/cm/sup-3/.

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Growth and characterization of bulk GaN single crystals by basic ammonothermal method (Basic 암모노써멀 방법에 의한 벌크 GaN 단결정의 성장 및 특성)

  • Shim, Jang Bo;Lee, Young Kuk
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.26 no.2
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    • pp.58-61
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    • 2016
  • Bulk GaN crystals were grown by the basic ammonothermal method. The c-plane GaN templates grown by hydride vapor phase epitaxy were used as seed crystals and sodium metal, amide, and azide were added as a mineralizer. The growth conditions are at temperatures from $500{\sim}600^{\circ}C$ and pressures from 2~3 kbar. The growth rate for the c-axis was increased with increasing the operating pressure. Average dislocation density was measured $1{\times}10^5/cm^2$ by the cathodoluminescence measurement. The full-width at half-maximum of the X-ray diffraction rocking curve for (002) reflection was approximately 270 arcsec for Ga face and 80 arcsec for N face.

Selective Growth of Nanosphere Assisted Vertical Zinc Oxide Nanowires with Hydrothermal Method

  • Lee, Jin-Su;Nam, Sang-Hun;Yu, Jung-Hun;Yun, Sang-Ho;Boo, Jin-Hyo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.08a
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    • pp.252.2-252.2
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    • 2013
  • ZnO nanostructures have a lot of interest for decades due to its varied applications such as light-emitting devices, power generators, solar cells, and sensing devices etc. To get the high performance of these devices, the factors of nanostructure geometry, spacing, and alignment are important. So, Patterning of vertically- aligned ZnO nanowires are currently attractive. However, many of ZnO nanowire or nanorod fabrication methods are needs high temperature, such vapor phase transport process, metal-organic chemical vapor deposition (MOCVD), metal-organic vapor phase epitaxy, thermal evaporation, pulse laser deposition and thermal chemical vapor deposition. While hydrothermal process has great advantages-low temperature (less than $100^{\circ}C$), simple steps, short time consuming, without catalyst, and relatively ease to control than as mentioned various methods. In this work, we investigate the dependence of ZnO nanowire alignment and morphology on si substrate using of nanosphere template with various precursor concentration and components via hydrothermal process. The brief experimental scheme is as follow. First synthesized ZnO seed solution was spun coated on to cleaned Si substrate, and then annealed $350^{\circ}C$ for 1h in the furnace. Second, 200nm sized close-packed nanospheres were formed on the seed layer-coated substrate by using of gas-liquid-solid interfacial self-assembly method and drying in vaccum desicator for about a day to enhance the adhesion between seed layer and nanospheres. After that, zinc oxide nanowires were synthesized using a low temperature hydrothermal method based on alkali solution. The specimens were immersed upside down in the autoclave bath to prevent some precipitates which formed and covered on the surface. The hydrothermal conditions such as growth temperature, growth time, solution concentration, and additives are variously performed to optimize the morphologies of nanowire. To characterize the crystal structure of seed layer and nanowires, morphology, and optical properties, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, and photoluminescence (PL) studies were investigated.

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Single-phase Gallium Nitride on Sapphire with buffering AlN layer by Laser-induced CVD

  • Hwang Jin-Soo;Lee Sun-Sook;Chong Paul-Joe
    • Bulletin of the Korean Chemical Society
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    • v.15 no.1
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    • pp.28-33
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    • 1994
  • The laser-assisted chemical vapor deposition (LCVD) is described, by which the growth of single-phase GaN epitaxy is achieved at lower temperatures. Trimethylgallium (TMG) and ammonia are used as source gases to deposit the epitaxial films of GaN under the irradiation of ArF excimer laser (193 nm). The as-grown deposits are obtained on c-face sapphire surface near 700$^{\circ}$C, which is substantially reduced, relative to the temperatures in conventional thermolytic processes. To overcome the lattice mismatch between c-face sapphire and GaN ad-layer, aluminum nitride(AlN) is predeposited as buffer layer prior to the deposition of GaN. The gas phase interaction is monitored by means of quadrupole mass analyzer (QMA). The stoichiometric deposition is ascertained by X-ray photoelectron spectroscopy (XPS). The GaN deposits thus obtained are characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and van der Pauw method.