• Title/Summary/Keyword: Crystallographic properties

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Crystallographic Orientation Dependence Of Electrical Properties of Carbon-doped GaAs Grown by Low Pressure Metalorganic Chemical Vapor Deposition Using CBr4 (저압 MOCVD로 CBr4 가스를 사용하여 탄소 도핑된 GaAs 에피층의 결정학적 방향에 따른 전기적 성질의 의존성)

  • 손창식
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.3
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    • pp.214-219
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    • 2002
  • In order to elucidate the crystallographic orientation dependence of electrical properties of carbon (C)-doped GaAs epilayers, C incorporation into GaAs epilayers on high-index GaAs substrates with various crystallographic orientations from (100) to (111)A has been performed by a low pressure metalorganic chemical vapor deposition using C tetrabromide ($CBt_4$) as a C source. The hole concentration of C-doped GaAs epilayers rapidly decreases with a hump at (311)A with increasing the offset angle. Although the growth temperature and the V/III ratio are varied, the crystallographic orientation dependence of hole concentration show a same trend. The above behaviors indicate that the bonding strength of As sites on a glowing surface plays an important role in the C incorporation into the high-index GaAs substrates.

The Symmetry of Aurivillius Ceramics

  • Fuentes, Luis;Fuentes, Maria E.;Camacho, Hector
    • Korean Journal of Crystallography
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    • v.12 no.4
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    • pp.227-232
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    • 2001
  • Structure-physical properties relationships for Aurivillius ceramics are discussed, with empha-sis in symmetry considerations. Single-crystal materials and polycrystal ceramics are analysed. Electric and magnetic coupling properties are considered. Colour Symmetry Groups and Texture Analysis tool are emploed. Symmetry conditions for polarisation vectors and inverse pole figures related to Aurivillius phases are given. The influence of crystallographic texture of the physical properties of polycrystalline Aurivillius ceramics is evaluated.

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Deposition of β-SiC by a LPCVD Method and the Effect of the Crystallographic Orientation on Mechanical Properties (저압 화학기상증착법을 이용한 β-SiC의 증착 및 결정 성장 방위에 따른 기계적 특성 변화)

  • Kim, Daejong;Lee, Jongmin;Kim, Weon-Ju;Yoon, Soon Gil;Park, Ji Yeon
    • Journal of the Korean Ceramic Society
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    • v.50 no.1
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    • pp.43-49
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    • 2013
  • ${\beta}$-SiC was deposited onto a graphite substrate by a LPCVD method and the effect of the crystallographic orientation on mechanical properties of the deposited SiC was investigated. The deposition was performed at $1300^{\circ}C$ in a cylindrical hot-wall LPCVD system by varying the deposition pressure and total flow rate. The texture and crystallographic orientation of the SiC were evaluated by XRD. The deposition rate increased linearly with the gas flow rate from 800 sccm to 1600 sccm. It also increased with the pressure but became saturated above a total pressure of 3.3 kPa. In the range of 3.3 - 10 kPa, the preferred orientation changed from the (220) and (311) planes to the (111) plane. The hardness and elastic modulus showed maximum values when the SiC had the (111) preferred orientation, though it gradually decreased upon a change to the (220) and (311) preferred orientations.