• Title/Summary/Keyword: X-ray diffraction(XRD)

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Effect of Basal-plane Stacking Faults on X-ray Diffraction of Non-polar (1120) a-plane GaN Films Grown on (1102) r-plane Sapphire Substrates

  • Kim, Ji Hoon;Hwang, Sung-Min;Baik, Kwang Hyeon;Park, Jung Ho
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.14 no.5
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    • pp.557-565
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    • 2014
  • We report the effect of basal-plane stacking faults (BSFs) on X-ray diffraction (XRD) of non-polar (11$\underline{2}$0) a-plane GaN films with different $SiN_x$ interlayers. Complete $SiN_x$ coverage and increased three-dimensional (3D) to two-dimensional (2D) transition stages substantially reduce BSF density. It was revealed that the Si-doping profile in the Si-doped GaN layer was unaffected by the introduction of a $SiN_x$ interlayer. The smallest in-plane anisotropy of the (11$\underline{2}$0) XRD ${\omega}$-scan widths was found in the sample with multiple $SiN_x$ layers, and this finding can be attributed to the relatively isotropic GaN mosaic resulting from the increase in the 3D-2D growth step. Williamson-Hall (WH) analysis of the (h0$\underline{h}$0) series of diffractions was employed to determine the c-axis lateral coherence length (LCL) and to estimate the mosaic tilt. The c-axis LCLs obtained from WH analyses of the present study's representative a-plane GaN samples were well correlated with the BSF-related results from both the off-axis XRD ${\omega}$-scan and transmission electron microscopy (TEM). Based on WH and TEM analyses, the trends in BSF densities were very similar, even though the BSF densities extracted from LCLs indicated that the values were reduced by a factor of about twenty.

Possibility about Application and Interpretation of Surface Nondestructive X-ray Diffraction Method for Cultural Heritage Samples by Material (유형별 문화재 시료의 비파괴 표면 X-선 회절분석법 적용과 해석 가능성)

  • Moon, Dong Hyeok;Lee, Myeong Seong
    • Journal of the Mineralogical Society of Korea
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    • v.32 no.4
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    • pp.287-301
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    • 2019
  • Preservation of the original form is the principle for conservation, management and utilization of cultural heritages. Thus, non-destructive analysis of these samples are important field of the conservation science. In this study, examined the applicability of nondestructive surface X-ray diffraction analysis (ND-XRD) for cultural heritage by materials (rock specimen, jade stone, pigment painted specimen, earthen artifact, metal artifact). In result, all type of sample is recorded suitable X-ray diffraction patterns for identifying mineral composition in case of surface condition with adequate particle size and arrangement. And diffraction pattern is reflected surface information than matrix. Therefore, ND-XRD is thought to be applicable not only mineral identification but also interpretation of manufacturing technique and alteration trend about layered sample (in horizontally or vertically). Whereas some exceptional diffraction patterns were recorded due to overlapping information on specific crystal planes. It caused by skip the sample treatment (powdering and randomly orientation). It could be advantageously used for mineral identification, such as preferred orientation of clay minerals. In contrast, irregular diffraction pattern caused by single crystalline effect is required careful evaluation.

Mineral Properties of Yangsan.Mulkum Clay (양산물금 점토의 광물학적 특성)

  • 정하익;이용수;진규남;진현식
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.10a
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    • pp.75-80
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    • 1999
  • In this study, clay sampled from Yangsan$.$Mulkum site were used to analyze mineral properties. Mineral and chemical properties of clay were investigated through X-ray fluorescence spectrometer(XRF), X-Ray Diffraction(XRD), and Scanning Electron Microscope(SEM) analysis. The result of this test represents that Yangsan$.$Mulkum clay are composed of quartz, albite, anorthite, orthocalse and illite.

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X-ray diffraction analysis of the effect of ball milling time on crystallinity of milled polyacrylonitrile-based carbon fiber

  • Lee, Sang-Hye;Kang, Dong-Su;Lee, Sang-Min;Roh, Jae-Seung
    • Carbon letters
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    • v.26
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    • pp.11-17
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    • 2018
  • Milled carbon fiber (mCF) was prepared by a ball milling process, and X-ray diffraction (XRD) diffractograms were obtained by a $2{\theta}$ continuous scanning analysis to study mCF crystallinity as a function of milling time. The raw material for the mCF was polyacrylonitrile-based carbon fiber (T700). As the milling time increased, the mean particle size of the mCF consistently decreased, reaching $1.826{\mu}m$ at a milling time of 18 h. The XRD analysis showed that, as the milling time increased, the fraction of the crystalline carbon decreased, while the fraction of the amorphous carbon increased. The (002) peak became asymmetric before and after milling as the left side of the peak showed an increasingly gentle slope. For analysis, the asymmetric (002) peak was deconvoluted into two peaks, less-developed crystalline carbon (LDCC) and more-developed crystalline carbon. In both peaks, Lc decreased and $d_{002}$ increased, but no significant change was observed after 6 h of milling time. In addition, the fraction of LDCC increased. As the milling continued, the mCF became more amorphous, possibly due to damage to the crystal lattices by the milling.

A Study on the Fabrication $Na_0.5$$K_0.5$$NbO_3$ Volatile Material Thin Film by Pulsed Laser Deposition and he Confirmation of C-axis Orientation by X-ray Diffraction (PLD 기법에 의한 $Na_0.5$$K_0.5$$NbO_3$ 휘발성 물질의 박막 제작 및 XRD에 의한 c축 배향성 확인에 관한 연구)

  • 최원석;김장용;장철순;문병무
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.4
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    • pp.269-273
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    • 2001
  • W fabricated thin film using Na$_{0.5}$K$_{0.5}$NbO$_3$ volatile material by pulsed laser deposition (PLD) and studied characterization from EM, XRD, P-E. The density and scale of droplet, which is the defect of PLD, was investigated by SEM but large droplet was not found. The degree of assemble oriented C-axis measured with X-ray diffraction suggests that this film oriented C-axis achieved by $\theta$-2$\theta$ scan and rocking curves shows good self-assemble phenomenon, finally $\phi$-scan does that all of the four directions of the lattice in film equals to those of substrate. P-E hysteresis loop shows residual remnant polarization or saturation polarization value, but it is applicable to memories.ies.

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Activation energy for the loss of substitutional carbon in $Si_{0.984}C_{0.016}$ grown by solid phase epitaxy

  • Kim, Yong-Jeong;Kim, Tae-Joon;Park, Byungwoo;Song, Jong-Han
    • Journal of Korean Vacuum Science & Technology
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    • v.4 no.2
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    • pp.50-54
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    • 2000
  • We studied the synthesis of S $i_{1-x}$ Cx (x=0.016) epitaxial layer using ion implantation and solid phase epitaxy (SPE). The activation energy Ea was obtained for the loss of substitutional carbon using fourier transform-infrared spectroscopy (FTIR) and high-resolution x-ray diffraction (HR-XRD). In FTIR analysis, the integrated peak intensity was used to quantify the loss of carbon atoms from substitutional to interstitial sites during annealing. The substitutional carbon contents in S $i_{0.984}$ $C_{0.016}$ were also measured using HR-XRD. By dynamic simulations of x-ray rocking curves, the fraction of substitutional carbon was obtained. The effects of annealing temperature and time were also studied by comparing vacuum furnace annealing with rapid thermal annealing (RTA))))))

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Ageing assessment of zirconia implant prostheses by three different quantitative assessment techniques

  • Kyaw, Phyu Phyu;Pongprueksa, Pong;Anuchitolarn, Warangkana;Sirinukunwatta, Krongkarn;Suputtamongkol, Kallaya
    • The Journal of Advanced Prosthodontics
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    • v.11 no.5
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    • pp.253-261
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    • 2019
  • PURPOSE. To evaluate the influence of cyclic loading on phase transformation of zirconia abutments and to compare the effectiveness of three different quantitative ageing assessment techniques. MATERIALS AND METHODS. Thirty two Y-TZP prostheses fabricated from two brands, InCoris ZI and Ceramill ZI, were cemented to titanium bases and equally divided into two subgroups (n=8): control group without any treatment and aged group with cyclic loading between 20 N and 98 N for 100,000 cycles at 4 Hz in distilled water at $37^{\circ}C$. The tetragonal-to-monoclinic phase transformation was assessed by (i) conventional x-ray diffraction (XRD), (ii) micro x-ray diffraction (${\mu}XRD$), and (iii) micro-Raman spectroscopy. The monoclinic-phase fractions (M%) were compared by two-way ANOVA. RESULTS. InCoris Zi presented significantly higher M% than Ceramill Zi in both control and aged groups (P<.001). Both materials exhibited significant phase transformation with monoclinicphase of 1 to 3% more in aged groups than controls for all three assessment techniques. The comparable M% was quantified by both ${\mu}XRD$ and XRD. The highest M% was assessed with micro-Raman. CONCLUSION. Cyclic loading produced significant phase transformation in tested Y-TZP prostheses. The micro-Raman spectroscopy could be used as an alternative to XRD and ${\mu}XRD$.

Estimation of Phase Ratio for TiO2 Powders by XRD and XAS (XRD와 XAS에 의한 TiO2 분말의 상분율 결정)

  • Rha, Sa-Kyun;Lee, Youn Seoung
    • Journal of the Korean Ceramic Society
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    • v.49 no.5
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    • pp.469-474
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    • 2012
  • The crystallinity and phase ratio of anatase to rutile in $TiO_2$ were estimated by x-ray diffraction (XRD) and x-ray absorption spectroscopy (XAS). Traditionally, the structural characterization of $TiO_2$ powders has been carried out by XRD techniques, which are comparatively easy in use and analysis. However, materials with amorphous phase, nano-sized or nano-structured crystallinities cannot be fully characterized by XRD because XRD analysis has a limit for abnormal contributions of the nano-crystal such as the surface contribution. From the comparison with the experimental and calculated Ti K-edge XAS spectra, we found the possibility of efficient estimation in the crystalinites and the phase ratio of anatase to rutile for nano-sized $TiO_2$ mixture.

Fire Performance Testing Method for Fire Retardant EPS Sandwich Panel Using X-ray Analysis (X-선 분석법을 이용한 난연 EPS 샌드위치 패널의 화재성능평가 방법에 관한 연구)

  • Shim, Ji-Hun;Cho, Nam-Wook
    • Fire Science and Engineering
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    • v.29 no.6
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    • pp.76-83
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    • 2015
  • EPS sandwich panel contains flame retardants that slow down ignition during fires,reduce the amount of heat generated, and block the spread of combustion. However, if a sandwich panel does not satisfy standards for fire-retardant performance, it may increase damage to property and human life. It is difficult to test the fire-retardant performance of a finishing material with the naked eye, so it is necessary to develop convenient and fast evaluation methods that are convenient and fast. In this study, a fire safety evaluation method for EPS sandwich panel was analyzed using X-ray to detect specific components related to the fire-retardant performance X-ray fluorescence analysis (XRF) indicated that suitable panel products contained more aluminum in comparison to unsuitable products. Gibbsite was identified as the main crystalline material of flame retardant EPS through X-ray diffraction analysis (XRD) and was included in both suitable products and unsuitable products, but there was a difference in crystalline structure. This study was verifies the possibility of evaluating fire-retardant performance using ultimate analysis and crystal analysis through these X-ray methods.

On the Crystalline Structures of Iron Oxides formed During Removal Process of Iron in Water (수중의 철 제거 시 생기는 산화철의 결정구조에 관한 연구)

  • Cho, Bong-Yeon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.1B
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    • pp.107-111
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    • 2006
  • The samples collected from two reactors are analyzed by X-ray diffraction and M$\ddot{o}$ssbauer spectroscopy in this study. It is concluded that the iron oxide crystal attached on anthracite media which possesses catalytic ability is identified to be Ferrihydrite, regardless of the value of pH from the analysis of the iron oxide. Iron oxide in Batch reactor is identified to be Microcrystalline goethite.