Atomic layer deposition of high-k oxides on graphene

Atomic layer deposition of high-k oxides on graphene.Comment: Graphene - Synthesis, Characterization, Properties and Applications, Jian Ru Gong (Ed.), ISBN: 978-953-307-292-0, InTech, Available from: http://www.intechopen.com/articles/show/title/atomic-layer-deposition-of-high-k-oxides-on-graphen

Structural, Vibrational, and Electronic Study of Sb2S3 at High Pressure

Antimony trisulfide (Sb2S3), found in nature as the mineral stibnite, has been studied under compression at room temperature from a joint experimental and theoretical perspective. X-ray diffraction and Raman scattering measurements are complemented with ab initio total-energy, lattice-dynamics, and electronic structure calculations. The continuous changes observed in the volume, lattice parameters, axial ratios, bond lengths, and Raman mode frequencies as a function of pressure can be attributed to the different compressibility along the three orthorhombic axes in different pressure ranges, which in turn are related to the different compressibility of several interatomic bond distances in different pressure ranges. The structural and vibrational properties of Sb2S3 under compression are compared and discussed in relation to isostructural Bi2S3 and Sb2Se3. No first-order phase transition has been observed in Sb2S3 up to 25 GPa, in agreement with the stability of the Pnma structure in Bi2S3 and Sb2Se3 previously reported up to 50 GPa. Our measurements and calculations do not show evidence either for a pressure-induced second-order isostructural phase transition or for an electronic topological transition in Sb2S3.This work has been performed under financial support from Spanish MINECO under Projects MAT2013-46649-C4-2/3-P and MAT2015-71070-REDC. This publication is fruit of "Programa de Valoracion y Recursos Conjuntos de I+D+i VLC/CAMPUS" and has been financed by the Spanish Ministerio de Educacion, Cultura y Deporte, as part of "Programa Campus de Excelencia Internacional" through Projects SP20140701 and SP20140871. These experiments were performed at BL04-MSPD beamline at ALBA Synchrotron with the collaboration of ALBA staff. Supercomputer time has been provided by the Red Espanola de Supercomputacion (RES) and the MALTA cluster. J.A.S. acknowledges financial support through Juan de la Cierva fellowship.Ibáñez, J.; Sans-Tresserras, JÁ.; Popescu, C.; López-Vidrier, J.; Elvira-Betanzos, J.; Cuenca Gotor, VP.; Gomis, O.... (2016). Structural, Vibrational, and Electronic Study of Sb2S3 at High Pressure. Journal of Physical Chemistry C. 19(120):10547-10558. https://doi.org/10.1021/acs.jpcc.6b01276S10547105581912

Occupational Commuting and Leisure-Time Physical Activity mong Occupational Categories in Estonia

[[abstract]]Background and purpose. Adults in lower status occupational groups are at higher risk of cardiovascular disease, for which physical inactivity is the major risk factor. Moderate and high levels of leisure time, occupational and commuting physical activity have been shown to be associated with a reduced CVD and all-cause mortality among both sexes. The purpose of the study is to examine occupational, commuting, leisure time and total physical activity and explore which occupational category in Estonia would be more likely sufficiently active or inactive for cardio-respiratory fitness. Method. The secondary data was obtained from the study Health Behavior among Estonian Adult Population 2006. The self-completion questionnaire was used to examine both self-reported occupational, commuting, leisure time, and total physical activity of adult professional, associate, machine operators and craftsman category for males (n=767) and professional, office clerks, service/sales worker, craftswomen, homemakers and elementary workers category for females (n=1097). Chi square analysis and logistic regression analysis were used to examine the associations between occupational category membership in different physical activity domain separately for male and female. Results. After adjustment for age, education, body mass index, marital status, nationality, smoking and income, this study has found that total physical activity is distinct among different occupational category; the higher risk groups of total physical inactivity are machine operators [OR=2.05 (0.94-4.49)] and professional workers [OR=1.67 (0.82-3.43)] category among male respondents and office clerks [OR=8.46 (3.26-21.94)], craftswomen [OR=4.90 (1.71-14.05)] and professional [OR=4.24 (1.56-11.57)] category among female respondents. Discussion. The findings are partially consistent with other studies, which have found lower status occupational workers to have higher total physical activity. But the exceptions of this study are the machine operators’ category for the male and craftswomen category for the female, who being also relatively lower occupational status, report higher total physical inactivity. Conclusion. Machine operators and professional category among male and office clerks, craftswomen and professional occupational category workers have higher total physical inactivity

Chloride atomic-layer chemical vapor deposition of TiO2 with a chloride pretreatment of substrates

A procedure for changing the course of the atomic-layer chemical vapor deposition (ALCVD) growth of TiO2 from TiCl4 and H2O on amorphous SiO2 substrates/underlayers at low temperatures is proposed. The changes are characterized by the real-time incremental dielectric reflection measurements and post-growth spectrophotometry and reflection high-energy electron diffraction measurements. In the procedure, an ultrathin layer of the material is deposited and, subsequently, in situ inhomogeneously etched in the TiCl4 flow, both steps being performed at a temperature above 350°C. As a result, an ultrathin microrough mixed amorphous/anatase-phase surface layer is created. By using this layer as a seed layer, the crystalline-growth temperature of the material is reduced. So anatase (mixed with amorphous phase) TiO2 thin films on SiO2 substrates at 125°C are, for the first time, grown. The films are shown to be depth-inhomogeneous. The upper part of the films, when they are thicker, is well texture

Raman modes in transferred bilayer CVD graphene

A systematic experimental Raman spectroscopic study of twisted bilayer graphene (tBLG) domains localized inside wide-area single layer graphene (SLG) produced by low-pressure CVD on Cu foil and transferred onto SiO2/Si substrate has been performed. According to the Raman characterization the tBLG domains had a great variety of twisting angles θ between the bottom and top graphene layers (6° < θ < 25°). The twisting angle θ was estimated from the spectral position of the rotating R and R' modes in the Raman spectrum.Under G band resonance conditions the breathing mode ZO' with a frequency of 95- 97 cm−1 was detected, and a breathing mode ZO was found in the spectra between 804 cm−1 and 836 cm−1, its position depending on the twisting angle θ. An almost linear relationship was found between the frequencies ωZO and ωR. Also a few other spectral peculiarities were found, e.g. a high-energy excitation of the G band resonance, the 2G overtone appearing at 3170-3180 cm−1 by the G band resonance, revealing a linear dispersion of 80 cm−1/eV of the 2D band in tBL