Raman Scattering in LiCoO2 Single Crystals and Thin Films

1997 ◽  
Vol 496 ◽  
Author(s):  
J. D. Perkins ◽  
M. L. Fu ◽  
D. M. Trickett ◽  
J. M. McGraw ◽  
T. F. Ciszek ◽  
...  
Keyword(s):  
Thin Film ◽  
Crystal Structure ◽  
Thin Films ◽  
Raman Scattering ◽  
Single Crystal ◽  
Single Crystals ◽  
Phonon Modes ◽  
Al Substitution ◽  
Scattering Measurements ◽  
Oriented Polycrystalline

ABSTRACTWe report Raman scattering measurements for uniaxially textured and randomly oriented polycrystalline LiCoO2 min films as well as for LiCoO2 and LiCo0.4Al0.6O2 single crystals. For both the crystalline LiCoO2 thin film samples and the single crystal LiCoO2 samples, well defined phonon modes are observed at Raman shifts of 486 cm−1 and 596 cm−1corresponding to the expected Eg and Alg modes of the layered LiCoO2 crystal structure with R3m symmetry. Upon Al substitution for Co in LiCoO2, the two phonon modes appear to shift to higher energy, but further work is needed to clarify this point.

HETEROEPITAXIAL GROWTH OF STRESS FREE SINGLE CRYSTAL PEROVSKITE THIN FILMS

2006 ◽  
Vol 13 (02n03) ◽  
pp. 167-172 ◽  
Author(s):  
K. WASA ◽  
S. H. SEO ◽  
D. Y. NOH ◽  
I. KANNO ◽  
T. SUZUKI
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Magnetron Sputtering ◽  
Single Crystal ◽  
Single Crystals ◽  
Structural Properties ◽  
Lattice Parameters ◽  
Heteroepitaxial Growth ◽  
Electromechanical Properties ◽  
Quenching Process

Thin films of single c-domain/single crystal ( PbMg 1/3 Nb 2/3 O 3)1-x( PbTiO 3)x, x = 0–0.4 (PMNT) were heteroepitaxially grown on (001) SrTiO 3 and (001) MgO substrates by magnetron sputtering using a quenching process. The lattice parameters of the quenched PMNT thin films were almost the same to the bulk values independently to the lattice parameters of substrates. The quenched PMNT thin films showed stress free structural properties, although the crystal structure of thin films is modified from bulk PMNT. The electromechanical properties are the same to the bulk single c-domain single crystals.

Organic thin films with charge-carrier mobility exceeding that of single crystals

2017 ◽  
Vol 5 (39) ◽  
pp. 10313-10319 ◽  
Author(s):  
Zachary A. Lamport ◽  
Ruipeng Li ◽  
Chao Wang ◽  
William Mitchell ◽  
David Sparrowe ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Charge Carrier ◽  
Single Crystal ◽  
Single Crystals ◽  
Carrier Mobility ◽  
High Mobility ◽  
Organic Thin Films ◽  
Charge Carrier Mobility

Through processing, spin-cast OTFTs outperform single-crystal OFETs by making accessible the high-mobility direction in the same crystal structure.

Physical properties of a transition metal oxide: optical and photoelectric properties of single crystal and thin film molybdenum trioxide

1968 ◽  
Vol 304 (1477) ◽  
pp. 211-231 ◽  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Single Crystal ◽  
Single Crystals ◽  
Molybdenum Trioxide ◽  
Polarized Light ◽  
Film Surface ◽  
Activation Energies ◽  
Temperature Range ◽  
Photoelectric Properties

The optical absorption spectra of single crystals and thin films of MoO 3 have been measured in the temperature range 150 to 340 °K with polarized light. At room temperature, the absorption spectrum of a single crystal consists of two peaks at λ 4130 and λ 3930 Å with E || C and only one absorption peak at 4250 Å with E ⊥ C followed by a rapid rise in absorption. The temperature and frequency dependence of the absorption coefficient in the edge over a range of absorption magnitudes 10 2 -10 5 cm -1 are described by expressions of the form K(v, T) = K 0 exp[— (β/kT) (E 0 — hv )]. The temperature dependence of the absorption edge was found to be linear from 340 to 150 °K with a temperature coefficient of — 6.2 x 10 -4 and — 9.3 x 10 -4 eV/°K for E || C and E ⊥ C , respectively. The corresponding temperature co­efficients in thin films are — 2.7 x 10 -4 and —4.0 x 10 -4 eV/°K for E|| and ⊥ to the film surface, respectively. Measurements have been made of the refractive indices of a single crystal and thin films. Ultraviolet irradiation of a thin film of MoO 3 produces a broad colour centre band having a maximum at 8700 Å. Several absorption peaks are resolvable in polarized light. On cooling down to 150 °K, the peak position shifts to shorter wavelength by 400 Å (4.67 x 10 -4 eV/°K). An e. s. r. signal with g = 2.001 ± 0.005 has been observed in the colour film. The electrical conductivity has been measured on single crystals and polycrystalline samples in the temperature range 25 to 500 °C, and the activation energies are found to be 1.83 ± 0.01 eV (intrinsic) and 0.29 to 0.70 eV (extrinsic). Photoconductivity has been measured in single crystals and thin films as a function of photon energy, temperature, and irradiation intensity. Trapping plays a significant role in the conduction phenomena. The thermal activation energies associated with different trapping levels were determined from the photoconductive decay curves and the electrical glow peaks measurements and were found to be in the range 0.16 to 0.64 eV.

Microstructure of Ca3Co4O9 Single Crystals and Thin Films

2005 ◽  
Vol 886 ◽  
Author(s):  
Yufeng Hu ◽  
Eli Sutter ◽  
Weidong Si ◽  
Qiang Li
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Single Crystal ◽  
Single Crystals ◽  
Single Crystal Sample ◽  
X Ray Diffraction ◽  
Crystal Sample ◽  
Lattice Constants ◽  
Glass Substrates ◽  
Transmission Electron

ABSTRACTWe present a comparative study of the microstructure of Ca3Co4O9 single crystals and c-axis oriented Ca3Co4O9 thin films grown on glass substrates. Though both crystals and films have similar values of Seekbeck coefficient and electric resistivity at room temperature, their microstructures are rather different. Extensive high resolution transmission electron microscopy (TEM) studies reveal that the films grown on glass substrates have abundant stacking faults, which is in contrast to the perfect crystalline structure found in the single crystal sample. The c-axis lattice constants derived from the x-ray diffraction (XRD) and TEM measurements for the single crystal sample and the thin film are virtually the same, suggesting that the thin film on the glass substrate was not strained.

scholarly journals Fabrication, micro-structure characteristics and transport properties of co-evaporated thin films of Bi2Te3 on AlN coated stainless steel foils

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aziz Ahmed ◽  
Seungwoo Han
Keyword(s):  
Thin Film ◽  
Crystal Structure ◽  
Thin Films ◽  
Stainless Steel ◽  
Substrate Temperature ◽  
Transport Properties ◽  
Structural Defects ◽  
Film Composition ◽  
High Substrate ◽  
Foil Substrate

AbstractN-type bismuth telluride (Bi2Te3) thin films were prepared on an aluminum nitride (AlN)-coated stainless steel foil substrate to obtain optimal thermoelectric performance. The thermal co-evaporation method was adopted so that we could vary the thin film composition, enabling us to investigate the relationship between the film composition, microstructure, crystal preferred orientation and thermoelectric properties. The influence of the substrate temperature was also investigated by synthesizing two sets of thin film samples; in one set the substrate was kept at room temperature (RT) while in the other set the substrate was maintained at a high temperature, of 300 °C, during deposition. The samples deposited at RT were amorphous in the as-deposited state and therefore were annealed at 280 °C to promote crystallization and phase development. The electrical resistivity and Seebeck coefficient were measured and the results were interpreted. Both the transport properties and crystal structure were observed to be strongly affected by non-stoichiometry and the choice of substrate temperature. We observed columnar microstructures with hexagonal grains and a multi-oriented crystal structure for the thin films deposited at high substrate temperatures, whereas highly (00 l) textured thin films with columns consisting of in-plane layers were fabricated from the stoichiometric annealed thin film samples originally synthesized at RT. Special emphasis was placed on examining the nature of tellurium (Te) atom based structural defects and their influence on thin film properties. We report maximum power factor (PF) of 1.35 mW/m K2 for near-stoichiometric film deposited at high substrate temperature, which was the highest among all studied cases.

Phenethylammonium bismuth halides: from single crystals to bulky-organic cation promoted thin-film deposition for potential optoelectronic applications

2019 ◽  
Vol 7 (36) ◽  
pp. 20733-20741 ◽  
Author(s):  
Mehri Ghasemi ◽  
Miaoqiang Lyu ◽  
Md Roknuzzaman ◽  
Jung-Ho Yun ◽  
Mengmeng Hao ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Surface Roughness ◽  
Single Crystals ◽  
Organic Cation ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Optoelectronic Applications ◽  
Excellent Stability

The phenethylammonium cation significantly promotes the formation of fully-covered thin-films of hybrid bismuth organohalides with low surface roughness and excellent stability.

Two lithium tricyanomethanide compounds: syntheses and single-crystal structure determination of LiK[C(CN)3]2 and Li[C(CN)3]·½ (H3C)2CO

2015 ◽  
Vol 70 (3) ◽  
pp. 191-196 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Single Crystals ◽  
Structure Determination ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Cell Parameters ◽  
New Compounds

AbstractThe new compounds LiK[C(CN)3]2 and Li[C(CN)3]·½ (H3C)2CO were synthesized and their crystal structures were determined. Li[C(CN)3]·½ (H3C)2CO crystallizes in the orthorhombic space group Ima2 (no. 46) with the cell parameters a=794.97(14), b=1165.1(2) and c=1485.4(3) pm, while LiK[C(CN)3]2 adopts the monoclinic space group P21/c (no. 14) with the cell parameters a=1265.7(2), b=1068.0(2) and c=778.36(12) pm and the angle β=95.775(7)°. Single crystals of K[C(CN)3] were also acquired, and the crystal structure was refined more precisely than before corroborating earlier results.

Calcium Carbodiimide Compounds Revisited – Syntheses, Single Crystal Structure Determination and Vibrational Spectra of Ca11N6[CN2]2, Ca4N2[CN2] and Ca[CN2]

2008 ◽  
Vol 63 (5) ◽  
pp. 530-536 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo
Keyword(s):  
Crystal Structure ◽  
Raman Spectrum ◽  
Single Crystal ◽  
Single Crystals ◽  
Vibrational Spectra ◽  
Structure Determination ◽  
X Ray ◽  
Characteristic Features ◽  
Reported Data ◽  
Correct Data

Single crystals of Ca11N6[CN2]2 (dark red needles, tetragonal, P42/mnm (no. 136), a = 1456.22(5), and c = 361.86(2) pm, Z = 2), Ca4N2[CN2] (transparent yellow needles, orthorhombic, Pnma (no. 62), a = 1146.51(11), b = 358.33(4), and c = 1385.77(13) pm, Z = 4) and Ca[CN2] (transparent, colorless, triangular plates, rhombohedral, R3̅m (no. 166), a = 369.00(3), and c = 1477.5(3) pm, Z = 3) were obtained by the reaction of Na2[CN2], CaCl2 and Ca3N2 (if demanded by stoichiometry) in arc-welded Ta ampoules at temperatures between 1200 - 1400 K. Their crystal structures were re-determined by means of single crystal X-ray structure analyses. Additionally, the Raman spectra were recorded on these same single crystals, whereas the IR spectra were obtained with the KBr pellet technique. The title compounds exhibit characteristic features for carbodiimide units with D∞h symmetry (d(C-N) = 121.7 - 123.8 pm and ∡ (N-C-N) = 180°). The vibrational frequencies of these units are in the expected range (Ca11N6[CN2]2: νs = 1230, νs = 2008; δ = 673/645/624 cm−1; Ca4N2[CN2]: νs = 1230, νs = 1986; δ = 672/647 cm−1; Ca[CN2]: νs = 1274, νs = 2031, δ = 668 cm−1). The structural results are more precise than the previously reported data, and with the newly attained Raman spectrum of Ca11N6[CN2]2 we correct data reported earlier.

scholarly journals Rubidium tetrafluoridobromate(III): redetermination of the crystal structure from single-crystal X-ray diffraction data

IUCrData ◽  
2019 ◽  
Vol 4 (11) ◽  
Author(s):  
Artem V. Malin ◽  
Sergei I. Ivlev ◽  
Roman V. Ostvald ◽  
Florian Kraus
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Single Crystals ◽  
Diffraction Data ◽  
Structure Type ◽  
X Ray Diffraction ◽  
X Ray ◽  
Square Planar ◽  
Atomic Coordinates

Single crystals of rubidium tetrafluoridobromate(III), RbBrF4, were grown by melting and recrystallizing RbBrF4 from its melt. This is the first determination of the crystal structure of RbBrF4 using single-crystal X-ray diffraction data. We confirmed that the structure contains square-planar [BrF4]− anions and rubidium cations that are coordinated by F atoms in a square-antiprismatic manner. The compound crystallizes in the KBrF4 structure type. Atomic coordinates and bond lengths and angles were determined with higher precision than in a previous report based on powder X-ray diffraction data [Ivlev et al. (2015). Z. Anorg. Allg. Chem. 641, 2593–2598].

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