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The spread of COVID-19 became the main public health risk for most countries in 2020. The Spanish government declared a state of emergency, implemented lockdown measures and imposed severe restrictions on mobility and compulsory home isolation. Given this sudden situation, we tested the levels of risk perception, the psychological impact of isolation conditions and of coping behaviors. A total of 1343 adult residents in Spain participated in the study. We measured with an online questionnaire (a) risk perception; (b) individual, social, and physical conditions of isolation; and (c) a set of coping behaviors. We tested how the conditions of isolation and the individual behavior affected positive and negative affect and meaning in life. We observed that risk perception was directly linked with the individual and social situation of the participants. Personal resilience, employment status, profile of cohabitants, and using open air spaces in the house are linked with the emotional situation of the participants. Additionally, we found that some behaviors were related with positive affect, meaning in life, and negative affect. The psychological impact of a nation-wide lockdown is not universal and there are key factors that moderate this impact. We have identified key personal, behavioral, social, and physical factors that may help policy makers and citizens in critical isolation situations

Ferroelectric nanofibers, based on the insertion of ferroelectric compounds into a polymer matrix, have been attracting strong interest due to their potential for technological applications, namely in sensors/actuators where their dielectric, pyroelectric and piezoelectric characteristics can be exploited. In this respect, nanofibers prepared by the versatile electrospinning technique present a high surface to- volume ratio and unique structure, allowing to tailor the fiber diameter down to the nanometer scale. Phenanthrene is an organic ferroelectric material that has been studied mainly in its bulk form and it has not been explored for the incorporation in functionalized nanostructures. As such, in this work we have studied the synthesis of phenanthrene nanofibers by electrospinning and their structural, dielectric and pyroelectric properties were characterized. The X-ray diffraction and Raman studies show that the prepared fibers are polycrystalline presenting the monoclinic ferroelectric structure. Scanning electron microscopy (SEM) measurements show that the fiber diameters are in the range 198-305 nm, being composed by phenanthrene inclusions embedded inside the polymer matrix. The temperature dependent permittivity studies indicate that the ferroelectric transition temperature (Tc) is ~ 75 ºC, similar to its bulk value (Tc,bulk = 72 ºC), with some hysteresis under temperature cycling. Pyroelectric measurements allowed to determine the pyroelectric coefficient, which similar to the bulk value. The observed behaviors were correlated with the nanosized character of the polar ferroelectric inclusions inside the synthesized nanofibers.

Raman spectroscopy results obtained for undoped and Al- and/or Mn-doped ZnO thin films produced by RF-sputtering are reported. The effect of the doping method (either co-sputtering or ion implantation), the dopant type and its concentration on the Raman-active vibrational modes in these films were studied in detail. The results are discussed with focus on the peak shifts and broadening, and on the doping-induced relaxation of the symmetry selection rules. A particular attention is paid to the 520-530 cm-1 Raman band observed in all Mn containing samples and a simple theoretical model and arguments are presented in support of its relation to the local (gap) phonon mode produced by Mn atoms substituting Zn in the cationic sublattice of the ZnO crystal., Karlsruhe Nano Micro Facility (KNMF), a Helmholtz Research Infrastructure at KIT

In this work, we report on the electrical characterization of Ge nanoparticles (NPs) produced by pulsed laser deposition (PLD) at room temperature (RT) in Ar gas inert atmosphere using a shadowed off-axis deposition geometry. Our results show that functional thin films of crystalline Ge NPs embedded between thin alumina films can be obtained on p-type Si(100) substrates following a low temperature and short rapid thermal annealing (RTA) treatment. Metal–oxide–semiconductor (MOS) structures with and without Ge NPs embedded in the alumina were prepared for the electrical measurements. The results indicate a strong memory effect at relatively low programming voltages (±4 V) due to the presence of Ge NPs., Fundação para a Ciência e a Tecnologia (FCT) - PTDC/FIS/70194/2006, SFRH/BPD/64850/2009 (FCT grant), COMPETE, COST MP0901-NanoTP Action, Cooperation program (FCT-CNRST)-2010/2012, Ref. 441.00

Comunicação oral, Semiconductor nanoparticles (NPs) are of great interest for multiple applications in the fields of photonics, optoelectronics, photovoltaics and biomedicine [1]. The ability to manage properly the size distribution and density in the fabrication process is of crucial relevance. In the literature, it can be found a large number of strategies for NPs production, including physical vapour deposition (PVD) methods. The main advantage of this technique, with respect to others, is the possibility to produce NPs in a free-contaminant inert atmosphere. In particular, pulsed laser deposition (PLD) technique is a versatile technique for producing NPs at room temperature (RT) when an inert gas atmosphere is introduced in the growth chamber [2]. Shadow mask or eclipse method has been demonstrated as an excellent approach for NPs size filtering, avoiding direct deposition of micron-sized particles usually produced in the ablation process [3]. In the nanometer scale, high-resolution microscopy techniques are essential to evaluate NPs sizes and density among other features, in order to optimize the NPs production process. In this work, we present scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies of NP films produced by PLD in an inert Argon gas atmosphere and under different deposition conditions, namely gas pressure, energy density and laser pulse frequency. We have combined shadow mask and off-axis configurations for NPs deposition. It is shown that, both NPs sizes and their distribution can be controlled precisely using adequate deposition conditions. WSxM software was used for AFM image processing and analysis [4]. [1] Andrey Rogach, Springer Wien New York (2010). [2] L. Patrone, D. Nelson, V. I. Safarov, M. Sentis, W. Marine, S. Giorgio, J. Appl. Phys. 87 (2000) 3829. [3] J. Martín-Sánchez, L. Marques, E.M.F. Vieira, Q.T. Doan, A. Marchand, A. El Hdiy, A.G. Rolo, S.R.C. Pinto, M.M.D. Ramos, A. Chahboun, M.J.M. Gomes, submitted to J. Nanopart. Res. [4] I. Horcas, R. Fernandez, J.M. Gomez-Rodriguez, J. Colchero, J. Gomez-Herrero, A.M. Baro, Review of Scientific Instruments, 78 (2007) 013705.

A Raman spectroscopy study of doped versus undoped ZnO layers is presented. The layers were grown by RF magnetron sputtering and the doping with Al, Sb and Mn was achieved by ion implantation with subsequent annealing. First-order Raman response measured under λ=488 nm excitation is discussed. It is shown that doping with any of the impurities used in this work produces a strong enhancement of the longitudinal optical (LO) phonon band, which is attributed to the intra-band Fröhlich mechanism. In addition, doping with Mn results in an extra mode located at 530 cm-1, tentatively attributed to a local vibrational mode of Mn substituting Zn in the lattice sites., FCT through project PTDC/FIS/72843/2006

Absorption of far-infrared (FIR) radiation and Raman scattering in CdTe nano-crystals (spherical quantum dots (QDs) of several nanometers in size) and Cd54Te32(SCH2CH2OH)8- 32 clusters prepared by colloidal synthesis were studied. Raman spectra of both QDs and clusters are dominated by a peak situated slightly below the bulk CdTe LO phonon frequency. Experimental FIR transmittance spectra of films containing CdTe clusters show a broad band between the bulk TO and LO phonon frequencies, while there is only a single dip at the Fro¨ hlich frequency observed for larger QDs. These observations are in agreement with the results of our numerical lattice dynamics calculations and previously published theoretical results based on a continuous model. It is suggested that the lattice dynamics of very small clusters is similar to that of large crystallites in the sense that there still exists the dispersion of optical vibration frequencies within the LO–TO band of bulk material., Fundação para a Ciência e a Tecnologia (FCT)