Korean | English

pISSN : 1225-1429 / eISSN : 2234-5078

2020 KCI Impact Factor : 0.17
Home > Explore Content > All Issues > Article List

2006, Vol.16, No.4

  • 1.

    Fluoride single crystals for UV/VUV nonlinear optical applications

    K. Shimamura | Encarnacion G. Villora | Kenichi Muramatsu and 2other persons | 2006, 16(4) | pp.133~140 | number of Cited : 0
    Abstract PDF
    The growth characteristics and properties of large size SrAlF5 single crystals are described and compared with those of BaMgF4. Transmission spectra in the vacuum ultraviolet wavelength region indicate a high transparency of SrAlF5 (about 90 % without considering surface reflection loses) down to 150 nm, on contrast to the optical loses observed for BaMgF4. The ferroelectric character of SrAlF5 is evidenced by the reversal of the spontaneous polarization in a hysteresis loop. The higher potential of SrAlF5 in comparison with BaMgF4 for the realization of all-solid-state lasers in the ultraviolet wavelength region by the quasi-phase matching (QPM) technique is pointed out. SrAlF5, besides a higher grade of transparency, shows a nonlinear effective coefficient similar to that of quartz and uniaxial nature, on contrast to the one order smaller nonlinear coefficient and biaxial character of BaMgF4. The refractive index of SrAlF5 from the ultraviolet to the near-infrared wavelength region is measured by the minimum deviation method. The Sellmeier and Cauchy coefficients are obtained from the fits to the curves of the ordinary and extraordinary refractive indices, and the grating period for the first order QPM is estimated as a function of the wavelength. The poling periodicity for 193 nm SHG from 386 nm is 4 mm.Key words Fluoride, SrAlF5, BaMgF4, Ferroelectric, Nonlinear optics, UV, SHG1. Introduction
  • 2.

    Conditions of Skull melting system for rutile single crystals growth

    SEOK, JEONG-WON | Choi Jong Keon | 2006, 16(4) | pp.141~148 | number of Cited : 1
    Abstract PDF
    Skull melting method can be a good candidate for growing oxide single crystals with high quality and for mass production because of its low production costs and high yield through recycling of crust. In this study, rutile single crystals were grown by the skull melting method and ingot characteristics with the variation of different growth conditions has been investigated. Conditions for high quality rutile ingot growth were used for producing cold-crucible size of ?12 cm×H14cm, capacity of 3000 pF tank condenser, work frequency of 2.84 MHz, melt-dwelling time of 9hrs and growing speed of 2 mm/h.Key words Skull melting, Rutile single crystal, Rutile ingot, Cold-cruclble루틸단결정 성장을 위한 스컬용융시스템의 조건석정원?, 최종건*동신대학교 보석공학과, 나주, 520-714*세라믹공정연구센터, 서울, 133-791(2006년 5월 30일 접수)(2006년 6월 15일 심사완료)
  • 3.

    Effect of aspect ratio on solutally buoyancy-driven convection in mercurous chloride (Hg2Cl2) crystalgrowth processes

    Geug-Tae Kim | Kyong-Hwan Lee | 2006, 16(4) | pp.149~156 | number of Cited : 1
    Abstract PDF
    For an aspect ratio (transport length-to-width) of 5, Pr = 2.89, Le = 0.018, Pe = 2.29, Cv = 1.11, PB = 40 Torr, solutally buoyancy-driven convection (Grs = 3.03 ? 105) due to the disparity in the molecular weights of the component A (Hg2Cl2) and B (He) is stronger than thermally buoyancy-driven convection (Grt = 1.66 ? 104). The crystal growth rate is decreased exponentially for 2.5 ? Ar ? 5, with (1) the linear temperature profile and a fixed temperature difference, (2) the imposed thermal profile, a fixed crystal region and varied temperature difference. This is related to the finding that the effects of side walls tend to stabilize convection in the growth reactor. But, with the imposed thermal profile, a fixed source region and varied temperature difference, the rate is increased for 2 ? Ar ? 3, and remains nearly unchanged for 3 ? Ar ? 5.Key words Mercurous chloride, Solutally buoyancy-driven convection, Aspect ratio, Physical vapor transport1. Introduction
  • 4.

    Characterization of In(Al)GaN layer grown by mixed-source hydride vapor phase epitaxy

    SUNLYEONG HWANG | JIho Chang | Hyung Soo Ahn and 8other persons | 2006, 16(4) | pp.157~161 | number of Cited : 1
    Abstract PDF
    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 NH3 gas were used as group III and group V source materials, respectively. The InGaN material was compounded from chemical reaction between NH3 and indium-gallium chloride formed 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.Key words HVPE, Mixed-source, InGaN, InAlGaN, XPS, CL, PL혼합소스 HVPE에 의해 성장된 In(Al)GaN 층의 특성황선령, 김경화, 장근숙, 전헌수, 최원진, 장지호, 김홍승, 양민, 안형수?, 배종성*, 김석환**한국해양대학교 반도체물리학과, 부산, 606-791*한국기초과학지원연구원 부산분소, 부산 609-735
  • 5.

    Growth of InGaN/AlGaN heterostructure by mixed-source HVPE with multi-sliding boat system

    장근숙 | KYOUNG HWA KIM | Min Yang and 8other persons | 2006, 16(4) | pp.162~165 | number of Cited : 0
    Abstract PDF
    The selective growth of InGaN/AlGaN light emitting diodes was performed by mixed-source hydride vapor phase epitaxy (HVPE). In order to grow the InGaN/AlGaN heterosturcture consecutively, a special designed multi-sliding boat was employed in our mixed-source HVPE system. Room temperature electroluminescence spectum of the SAG-InGaN/AlGaN LED shows an emission peak wavelength of 425 nm at injection current 20 mA. We suggest that the mixed-source HVPE method with multi-sliding boat system is possible to be one of the growth methods of III-nitrides LEDs.Key words HVPE, LED, SAG, EL, I-V, InGaN/AlGaN heterostructure, Multi-sliding boat systemMulti-sliding boat 방식을 이용한 혼합소스 HVPE에 의한 InGaN/AlGaN 이종접합구조의 성장장근숙, 김경화?, 황선령, 전헌수, 최원진, 양민, 안형수, 김석환*, 유재은**, 이수민**, M. Koike**한국해양대학교 반도체물리학과, 부산, 606-791*안동대학교 물리학과, 안동, 760-749
  • 6.

    Microwave-assisted synthesis of Cu2O and Cu from Cu2(OH)3(CH3COO)?2O

    송하철 | Young Duk Huh | 2006, 16(4) | pp.166~171 | number of Cited : 0
    Abstract PDF
    Cu2O and Cu have been synthesized from the layered organic-inorganic hybrid, Cu2(OH)3(CH3COO)?H2O, assisted by microwave irradiation. Cu2O is formed in aqueous glucose solution, while metallic Cu is formed in ethylene glycol by reduction of Cu2(OH)3(CH3COO)?H2O. The influence of microwave irradiation time and concentration of glucose on Cu2O particles formation and growth has been examined. The morphologies of Cu2O particles change from spheres with a few mm size to nanowires with diameter of 40 nm as increasing the microwave irradiation times.Key words Cu2O, Metallic Cu, Organic-inorganic hybrid, MicrowaveCu2(OH)3(CH3COO)·H2O로 부터 마이크로파를 이용한 Cu2O와 Cu의 합성송하철, 허영덕?단국대학교 화학과, 서울, 140-714(2006년 7월 3일 접수)(2006년 7월 26일 심사완료)
  • 7.

    Mechanical properties of Al2O3/Mo/MnO2 composite

    Hyun Park | Kim Kyung Nam | 2006, 16(4) | pp.172~179 | number of Cited : 0
    Abstract PDF
    When Al2O3-MoO3 mixture is reduced, MoO3 is only reduced to Mo at 900oC. But a compound between Al2O3 and Mo is not formed up to 1300oC. In the case of Al2O3-MoO3-MnO2 mixture, an intermediate compound Mn2Mo3O8 is firstly formed at 900oC and changes to MnAl2O4 at 1100oC~1300oC. Al2O3/Mo/MnO2 composite are manufactured by a selective reduction process in which Mo is only reduced in the powder mixture of Al2O3, MoO3 and MnO2 oxide. For Al2O3/Mo composite, the average grain size was not changed with increasing Mo content because of inhibition of grain growth of Al2O3 matrix in the presence of Mo particles. Fracture strength increased with increasing Mo content due to phenomenon of grain growth inhibition of Al2O3 matrix. Hardness decreased because of a lower hardness value of Mo, whereas fracture toughness increased. For Al2O3/Mo/MnO2 composite, grain growth was facilitated by MnO2 and it showed a lower fracture strength because of grain growth effect with increasing Mo and MnO2 content. Hardness decreased because of the grain growth of matrix and coalesced Mo particles to be located in grain boundary, whereas fracture toughness increased.Key words Al2O3/Mo/MnO2 composite, Selective reduction process, Hot pressingAl2O3/Mo/MnO2 복합재료의 기계적 특성박현?, 김경남강원대학교 신소재화학공학부, 삼척, 245-711(2006년 7월 19일 접수)(2006년 8월 4일 심사완료)