Effect of thermal annealing on the strain and microstructures of in-situ phosphorus-doped _{Si 1 − x} _{C x} films grown on blanket and patterned silicon wafers

Kim, Sun-Wook,Lee, Minhyeong,Jang, Hyunchul,Lee, Hoo-Jeong,Ko, Dae-Hong Elsevier 2019 Journal of alloys and compounds Vol.790 No.-

<P><B>Abstract</B></P> <P>In this study, in-situ phosphorus-doped <SUB> Si 1 − x </SUB> <SUB> C x </SUB> layers were epitaxially grown on blanket and patterned Si wafers using reduced pressure chemical vapor deposition (RPCVD). The effect of post-growth annealing on the strain and microstructures of the epilayers was investigated by high resolution X-ray diffraction (HR-XRD), Raman scattering, and high resolution transmission electron microscopy (HR-TEM) analyses. Structural investigation revealed that induced tensile strain became significantly less at temperatures over 900°, as confirmed by Raman scattering measurements of SiC vibration modes. Furthermore, strain relaxation and substantial C<SUB> <I>sub</I> </SUB> loss were found in XRD and Raman data of Si:C samples annealed at 1000°, resulting from the generation of defects such as β-SiC precipitates or dislocations in <SUB> Si 1 − x </SUB> <SUB> C x </SUB> epilayers. Moreover, our microstructural analyses using TEM showed the formation of the β-SiC precipitates during rapid thermal annealing (RTA) over 900° and an increase in their number and size with annealing temperatures up to 1000°. Finally, we examined the impact of thermal annealing on the local strain and microstructures of patterned <SUB> Si 1 − x </SUB> <SUB> C x </SUB> samples with different structures. Our findings will provide greater insight into evaluating the strain states and microstructure of as-grown and annealed P-doped <SUB> Si 1 − x </SUB> <SUB> C x </SUB> films on both blanket and patterned Si wafers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> In-situ P-doped Si<SUB>1−x</SUB>C<SUB>x</SUB> films were grown on Si substrates using a RPCVD system. </LI> <LI> The impact of thermal annealing on the strain and microstructures was examined. </LI> <LI> Significant loss in induced tensile strain was confirmed by XRD and Raman measurements. </LI> <LI> TEM analyses provided direct evidence of the microstructural changes in the films. </LI> </UL> </P>

X-Ray Diffraction line profile analysis of defects and precipitates in high displacement damage neutron-irradiated austenitic stainless steels

Shreevalli M.,Kumar Ran Vijay,Divakar R.,Ashish K.,Padmaprabu C.,Karthik V.,Sagdeo Archna 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.1

Irradiation-induced defects and the precipitates in the wrapper material of the Indian Fast Breeder Test Reactor (FBTR), SS 316 are analyzed using the synchrotron source-based Angle Dispersive X-Ray Diffraction (ADXRD) technique with X-rays of energy 17.185 keV (wavelength ~0.72146 Å). The differences and similarities in the high displacement damage samples as a function of dpa (displacement per atom) and dpa rate in the range of 2.9 × 10 7- 9 × 10 7 dpa/s are studied. Ferrite and M23C6 are commonly observed in the present set of high displacement damage 40–74 dpa SS 316 samples irradiated at temperatures in the range of 400–483 ◦C. Also, the dislocation density has increased as a function of the irradiation dose. The X-ray diffraction peak profile parameters quantified such as peak shift and asymmetry show that the irradiation-induced defects are sensitive to the dpa rate-irradiation temperature combinations. The increase in yield strength as a function of displacement damage is also correlated to the dislocation density

[C70]풀러렌 산화 반응의 거동에 관한 초음파 분광학적 고찰

고원배 ( Weon Bae Ko ) 한국고무학회 2014 엘라스토머 및 콤포지트 Vol.49 No.2

1,2-dichlorobenzene용액에서 [C70]풀러렌 과 3-chloroperoxy benzoic acid 산화반응의 거동을 고분해능 초음파 분광기를 사용하여 고찰하였다. UV-vis spectroscopy, X-ray diffraction 을 가지고 [C70]풀러렌 산화 반응의 생성물을 확인하였다. High resolution ultrasonic spectroscopy was used to observe the oxidation of [C70]fullerene with 3-chloroperoxy benzoic acid in 1,2-dichlorobenzene. UV-vis spectroscopy and X-ray diffraction confirmed the resulting products of [C70] fullerene oxidation.

Si (001) 기판에서 $N_2$처리에 의해 형성된 에피택셜 C49-$TiSi_2$상의 열적 거동과 결정학적 특성에 관한 연구

양준모,이완규,박태수,이태권,김중정,김원,김호정,박주철,이순영,Yang, Jun-Mo,Lee, Wan-Gyu,Park, Tae-Soo,Lee, Tae-Kwon,Kim, Joong-Jung,Kim, Weon,Kim, Ho-Joung,Park, Ju-Chul,Lee, Soun-Young 한국재료학회 2001 한국재료학회지 Vol.11 No.2

$N_2$처리에 의해 Si (001) 기판에 형성된 C49상의 구조를 갖는 에피택셜 $TiSi_2$상의 열적 거동과 결정학적 특성을 X선 회절법 (XRD)과 고분해능 투과전자현미경법 (HRTEM)으로 조사하였다. 에피택결 $C49-TiSi_2$상은 $1000^{\circ}C$ 정도의 고온에서도 안정상인 C54상으로 상변태하지 않고 형태적으로도 고온 특성이 우수하다는 것이 밝혀졌다. HRTEM 결과로부터 에피택결 $TiSi_2$상과 Si 사이의 결정학적 방위관계는 (060) [001]TiSi$_2$//(002) [110]Si임을 알 수 있었고 계면에서의 격자 변형에너지는 misfit 전위의 형성에 의하여 해소되는 것을 확인할 수 있었다. 또한 HRTEM상의 해석과 원자 모델링을 통하여 Si에서 에피택셜 C49-TiSi$_2$상의 형성기구와 C49상의 (020) 면에 존재하는 적층결함을 고찰하였다. The thermal behavior and the crystallographic characteristics of an epitaxial $C49-TiSi_2$ island formed in a Si (001) substrate by $N_2$, treatment were investigated by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). It was found from the analyzed results that the epitaxial $C49-TiSi_2$ was thermally stable even at high temperature of $1000^{\circ}C$ therefore did not transform into the C54-stable phase and did not deform morphologically. HRTEM results clearly showed that the epitaxial $TiSi_2$ phase and Si have the orientation relationship of (060)[001]$TiSi_2$//(002)[110]Si, and the lattice strain energy at the interface was mostly relaxed by the formation of misfit dislocations. Furthermore, the mechanism on the formation of the epitaxial $_C49-TiSi2$ in Si and stacking faults lying on the (020) plane of the C49 Phase were discussed through the analysis of the HRTEM image and the atomic modeling.

Structural and magnetic properties of lithium cathode materials Li_xFe_1/3Co_1/3Ni_1/3PO₄ (x=0, 1)

Choi, Hyunkyung,Kim, Hyung Joon,Shim, In-Bo,Lee, In Kyu,Kim, Chul Sung Elsevier 2017 Materials research bulletin Vol.93 No.-

<P><B>Abstract</B></P> <P>LiFe<SUB>1/3</SUB>Co<SUB>1/3</SUB>Ni<SUB>1/3</SUB>PO<SUB>4</SUB> and its fully deintercalated Fe<SUB>1/3</SUB>Co<SUB>1/3</SUB>Ni<SUB>1/3</SUB>PO<SUB>4</SUB> compounds were prepared by the vacuum-sealed solid state reaction method, and chemical-oxidation process with reaction of LiFe<SUB>1/3</SUB>Co<SUB>1/3</SUB>Ni<SUB>1/3</SUB>PO<SUB>4</SUB> and No<SUB>2</SUB>BF<SUB>4</SUB> in acetonitrile. The crystal structure of LiFe<SUB>1/3</SUB>Co<SUB>1/3</SUB>Ni<SUB>1/3</SUB>PO<SUB>4</SUB> is orthorhombic with the space group of <I>P</I>nma, which is same as Fe<SUB>1/3</SUB>Co<SUB>1/3</SUB>Ni<SUB>1/3</SUB>PO<SUB>4</SUB> during deintercalation. Temperature-dependent magnetization curves of Li<SUB>x</SUB>Fe<SUB>1/3</SUB>Co<SUB>1/3</SUB>Ni<SUB>1/3</SUB>PO<SUB>4</SUB> exhibit the enhancement of antiferromagnetic ordering due to the valence transition of transition metal ions with the increase in the Néel temperature from 35K for x=0 to 51K for x=1. The room-temperature Mössbauer spectra shows the valence transition with the LiFe<SUB>1/3</SUB>Co<SUB>1/3</SUB>Ni<SUB>1/3</SUB>PO<SUB>4</SUB> exhibiting Fe<SUP>2+</SUP> doublet whereas fully deintercalated Fe<SUB>1/3</SUB>Co<SUB>1/3</SUB>Ni<SUB>1/3</SUB>PO<SUB>4</SUB> showing one Fe<SUP>3+</SUP> doublet induced by the lithium ion diffusion. Experimental determined effective moment of Li<SUB>x</SUB>Fe<SUB>1/3</SUB>Co<SUB>1/3</SUB>Ni<SUB>1/3</SUB>PO<SUB>4</SUB> was found to be 5.63 <I>μ</I> <SUB>B</SUB> for x=0 and 6.95 <I>μ</I> <SUB>B</SUB> for x=1, which can be interpreted as incomplete absence of orbital contribution by crystal field around distorted MO<SUB>6</SUB> octahedron.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Li<SUB>x</SUB>Fe<SUB>1/3</SUB>Co<SUB>1/3</SUB>Ni<SUB>1/3</SUB>PO<SUB>4</SUB> (x=0, 1) material were synthesized via a solid state reaction method. </LI> <LI> Chemical delithiaition was performed by using NO<SUB>2</SUB>BF<SUB>4</SUB> oxidizing agent. </LI> <LI> The magnetic Néel temperatures of Li<SUB>x</SUB>Fe<SUB>1/3</SUB>Co<SUB>1/3</SUB>Ni<SUB>1/3</SUB>PO<SUB>4</SUB> were determined to be 51 for x=0 and 35K for x=1. </LI> <LI> The valence state of Fe ion can be provided the understanding of the charge/discharge mechanism for lithium-ion battery. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Structural and dielectric properties of Ba3V2O8 ceramics

Praveen Khatri,V. Srinivas,Banarji Behera,R.N.P. Choudhary 한국물리학회 2009 Current Applied Physics Vol.9 No.3

Polycrystalline sample of Ba3V2O8 was prepared by a high-temperature solid-state reaction technique. Preliminary X-ray diffraction (XRD) analysis confirms the formation of single-phase compound of hexagonal (rhombohedral) crystal structure at room temperature. Microstructural analysis by scanning electron microscope (SEM) shows that the compound has well defined grains, which are distributed uniformly throughout the surface of the sample. The dielectric properties of the compound studied in a wide frequency range (102– 106 Hz) at different temperatures (25–400 ℃), exhibits that they are temperature dependent. Detailed analysis of impedance spectra showed that the electric properties of the material are strongly dependent on frequency and temperature. The activation energy, calculated from the temperature dependence of ac conductivity (dielectric data), was found to be 0.23 eV at 50 kHz in the higher temperature region. Polycrystalline sample of Ba3V2O8 was prepared by a high-temperature solid-state reaction technique. Preliminary X-ray diffraction (XRD) analysis confirms the formation of single-phase compound of hexagonal (rhombohedral) crystal structure at room temperature. Microstructural analysis by scanning electron microscope (SEM) shows that the compound has well defined grains, which are distributed uniformly throughout the surface of the sample. The dielectric properties of the compound studied in a wide frequency range (102– 106 Hz) at different temperatures (25–400 ℃), exhibits that they are temperature dependent. Detailed analysis of impedance spectra showed that the electric properties of the material are strongly dependent on frequency and temperature. The activation energy, calculated from the temperature dependence of ac conductivity (dielectric data), was found to be 0.23 eV at 50 kHz in the higher temperature region.

Synthesis and Electrochemical Performance of LiMn_xFe_(x-1)PO_4/C Cathode Material for Lithium Secondary Batteries

김현수,Kyung Min Jin,Bong Soo Jin,Hoe-Jin Koo,Guoxiou Wang,Woo-Seong Kim 대한금속·재료학회 2011 METALS AND MATERIALS International Vol.17 No.5

Carbon-coated LiMn_0.8Fe_0.2PO_4/C (C = 5 wt.%, 10 wt.%, 15 wt.%, and 20 wt.%) cathode material is synthesized using a solid-state method. No impurity is found within the synthesized active material, which is confirmed to have an olivine structure with particle sizes in the range of 100 nm to 200 nm. The LiMn_0.8Fe_0.2PO_4/C (C = 10 wt.%) active material shows an outstanding discharge capacity of 121.7 mAh·g^(−1), along with a high capacity maintenance rate of 87.9 % at 2 C against the 0.2 C rate. In addition, this sample shows the most outstanding discharge capacity and coulombic efficiency in the cycling performance tests.

Highly modulated structure and upconversion photoluminescence properties of PbGd₂(MoO₄)₄:Er³⁺/Yb³⁺ phosphors

Pergamon Press 2016 Materials research bulletin Vol.75 No.-

<P>Double molybdate of PbGd2-x(MoO4)(4):Er3+/Yb3+ phosphors with the correct doping concentrations of Er3+ and Yb3+ (x= Er3+ + Yb3+, Er3+ = 0.05, 0.1, 0.2 and Yb3+ = 0.2, 0.45) were successfully synthesized by microwave sol-gel process. The highly modulated structure and the upconversion photoluminescence properties were investigated in detail. The synthesized particles, formed after heat-treatment at 900 degrees C for 16 h, showed a well ctystallized morphology with particle sizes of 2-5 mu m. Under excitation at 980 nm, the PbGd1.7(MoO4)(4):Er(0.1)Ybo(0.2) and PbGd1.5(MoO4)(4):Er0.05Yb0.45 particles exhibited a strong 525-nm emission band, a weak 550-nm emission band in the green region, and a very weak 655-nm emission band in the red region. The Raman spectra of the doped particles indicated the disordered structures of PbGd2-x(MoO4)(4) by the incorporation of the Er3+ and Yb3+ ions into the crystal lattice, which resulted in the highly modulated structure as well as a concentration quenching effect of Er3+ ions. (C) 2015 Published by Elsevier Ltd.</P>

[(η5-Cp)Co]2(1,2-S,S-o-Carborane) (C12H20B10S2Co2)의 합성 및 결정구조

조성일 한국결정성장학회 2008 韓國結晶成長學會誌 Vol.18 No.2

An Organometallic compound, C12H20B10S2Co2, was synthesized from o-carborane, Cp*Co(S2C2B10H10) and BH3·THF. The molecular structure of this complex has been determined by X-ray diffraction. Crystallographic data: monoclinic, space group Cc, a = 15.981(4) Å, b = 15.478(17) Å, c = 12.0562(17) Å, β = 115.063(16)o, Z = 4, V = 9683(4) Å3. The structure was solved by direct methods and refined by full-matrix leat-squares methods to give a model with a reliability factor R = 0.0630 for 9948 reflections.

Characteristic of Organic Thin Film Depending on Carbon Content by Fourier Transform Infrared Spectra and X-ray Diffraction Pattern

Teresa Oh 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.9