Skip to main content
Bicocca Open Archive Research Data

Datasets within this collection

Filter Results
264 resultsSearch results powered by
  • Dropen_V01
    Dropen is a fully automatic drop image analysis software in order to study the wetting properties of solid surfaces. It also includes the manual selection and fitting approaches. This software is developed in MATLAB using GUIDE. Regarding the identification of contact points two approaches are provided in Dropen: 1. Automatic: determines the left and right contact points automatically using a precise image processing code; 2. Manual: let the user select the left and right contact points manually by pushing the “Manual selection” button. In the case of the wrong selection of contact points the software let the user try two more times without a need to push the “Manual selection” button again. Regarding the contact angle measurement, the software provides a fully- automatic convolution mask method and also fitting with the circle and polynomial equations. So, the contact angle measurement panel includes: 1. Mask method: the fully automatic contact angle measurement, 2. Fitting: includes: a. Circle b. Polynomial: user can change the polynomial order. Regarding our studies, the optimum polynomial order for superhydrophilic droplets is two and for the rest of the droplets is Three. So, it is recommended to do not to change the polynomial order. After choosing the contact point identification and contact angle measurement methods, push the RUN button to find the results in the Result panel. In addition, the magnified images of the left and right contact areas are presented there. The drop contour line and the contact points have been shown with blue and red markers on the image, respectively. It is possible to save the contact angle data, as well as the left and right contact area images by pushing the corresponding push buttons. This software is developed in SEFILAB at the Department of Materials science, University of Milano-Bicocca, and is available at the UNIMIB repository (http://dx.doi.org/10.17632/wzchzbm58p.3). This repository will be updated by the new modified versions of the software.
    • Other
    • Software/Code
    • Image
    • Dataset
  • ODMR_pentacene_picene_single_crystal
    ODMR_pentacene_picene_single_crystal
    • Dataset
  • Data for: Contrast sensitivity and visual acuity with multifocal contact lenses with high additions dedicated for myopia progression control
    • Dataset
  • Data for: An empirical model of the sunlight bleaching efficiency of brick surfaces
    Supplementary Data: pages 2-12: daily mean global radiation (column 3, W/m2) pages 13-23: daily mean relative humidity (column 3, %) pages 24-34: daily mean global temperature (column 3, °C)
    • Dataset
    • Document
  • DC-01 - Magnetotransport and ARPES studies of large-area Sb2Te3 and Bi2Te3 topological insulators grown by MOCVD on Si
    Abstract: Chalcogenide thin films have become of interest in energy conversion, as thermoelectric materials, and for spintronic applications. Amongst them, antimony telluride (Sb2Te3) and bismuth telluride (Bi2Te3) have gained attention as Topological Insulators (TI) [1,2]. In order to make a step toward technology transfer, it is of major importance to achieve epitaxial quality-TI on large area, Si-based substrates.We have recently developed Metal Organic Chemical Vapor Deposition (MOCVD) processes to grow Bi2Te3 and Sb2Te3 thin films on top of 4” Si(111) substrates [1,3]. In this contribution we report clear evidence of the existence of topologically-protected surface states (TSS) in both ~90 nm-thick Bi2Te3 and ~30 nm-thick Sb2Te3 films by making use of magnetotransport (MR) and angle resolved photoemission spectroscopy (ARPES) studies.MR measurements were performed in the Van der Pauw configuration on ~1 x 1 cm2 samples without any processing or capping layers, in the 5-295 K temperature range.Following MR, samples were analysed by ex situ ARPES. In order to make this possible, prior to ARPES, the samples were cleaned under vacuum by 1.5 keV Ar ion sputtering for about 15 sec at 10-5 mbar. The sputtering cycles were repeated as many times as necessary to obtain a clean surface free of C and O contaminants, as verified by in situ X-ray photoelectron spectroscopy. As a final step, annealing under vacuum was performed at 290 °C for ~10 min, in order to recover the damage induced by Ar+ sputtering. Finally, flat and well-ordered surfaces were obtained, as checked by streaky reflection high-energy electron diffraction patterns. ARPES spectra were acquired at room temperature with a 100 mm hemispherical electron analyzer equipped with a 2D CCD detector (SPECS). The He I (21.22 eV) resonant line was used to excite photoelectrons and the energy resolution of the system was greater than 40 meV.Both Sb2Te3 and Bi2Te3 films exhibited a metallic behaviour, reaching a resistivity of 0.83 mΩ cm and 1.4 mΩ cm at 5 K, respectively. From Hall measurements, we identified the carrier type, being holes in Sb2Te3 and electrons in Bi2Te3, as expected. The evolution of the carrier density with the lowering of the temperature turned out to be different for the two samples: an increasing of the hole density for the Sb2Te3 and a decreasing of the electron density for the Bi2Te3 were observed. The corresponding mobilities displayed a maximum at 5 K, suggesting a suppression of bulk conduction at low temperature with a potentially higher contribution from the TSS. Quite interestingly, at 5 K, we detected a 430% increase of electron mobility in Bi2Te3, to be compared with a marginal 6% increase of hole mobility in the case of Sb2Te3. In both Sb2Te3 and Bi2Te3, MR measurements highlighted the presence of clear weak antilocalization (WAL) at low temperature, as shown in figures 1 and 2. WAL was interpreted in the framework of the Hikami-Larkin-Nagaoka (HLN) model as a first proof of the existence of 2D-conduction channels connected to TSS [4]. The two HLN parameters α (being connected to the number of conducting channels) and the coherence length (lφ) were extracted by fitting the magnetoconductance values (MC). The α values were 0.3 and 0.8 for Sb2Te3 and Bi2Te3 respectively, meaning that in Bi2Te3 the 2D-conduction is highly dominating when compared to Sb2Te3, in agreement with the corresponding temperature behaviour of electron and hole mobilities. At 5.5 K, the lφ reached the value of 74 nm in Bi2Te3 and 55 nm in Sb2Te3, again indicating a more favourable TSS-connected transport in Bi2Te3 than in Sb2Te3. Comparing the obtained α and lφ values with those reported in the literature for Bi2Te3 grown by MBE [5], we observe a very similar value for α and a slightly lower coherence length for our material. For what concerns Sb2Te3, the obtained α and lφ values are still lower than those previously reported for Sb2Te3 grown by MBE [6].As clearly shown in the insets of figures 1 and 2, ARPES measurements evidenced the typical Dirac-like band structure represented by a linear dispersion relation in both Sb2Te3 and Bi2Te3 (Fermi level EF is placed at 0 eV). ARPES showed that for both Sb2Te3 and Bi2Te3, the Dirac point is not exactly at EF, cutting the valence band in Sb2Te3 and the conduction band in Bi2Te3, in accordance with Hall measurements. ARPES data were in nice agreement with the partial overlap between TSS and bulk conduction observed at low T in transport measurements. This is most likely the explanation why, for both materials, we did not reach the ideal α=1 value expected for a pure TSS conduction.Our results showed that the TI properties of Bi2Te3 and Sb2Te3 grown by MOCVD on large areas Si substrates, are approaching those obtained by state-of-the-art methods, such as MBE, thus making a fundamental step toward potential technology transfer of TI. On the other hand, to enhance the TSS contribution in the MOCVD-grown TIs and, therefore, their functionalities, the Fermi level must be moved in the bulk band gap, closer to the Dirac point. [7] References: [1] R. Cecchini, R. Mantovan,.. and M. Longo, Phys. Status Solidi PRL, Vol 12(8), 1800155 (2018)[2] Y. L. Chen, J. G. Analytis,.. and Z. X. Shen, Science 325, 178-181 (2009)[3] M. Rimoldi, R. Cecchini,.. and R. Mantovan, RSC Advances, Vol 10(34), 19936-19942 (2020)[4] S. Hikami, A. I. Larkin, Y. Nagaoka, Prog. Theor. Phys., Vol 63(2), 707-710 (1980)[5] A. Roy, S. Guchhait, .. and S. K. Banerjee, Apl, Phys. Lett., 102(16) 163118, (2013)[6] Y. Takagaki, A. Giussani, & R. Calarco, J. Phys.: Condens. Matter 25(34), 345801 (2013)[7] C. Chang, P. Tang,.. & Q. Xue, Phys. Rev. Lett.115(13) 136801 (2015) Images: https://s3.eu-west-1.amazonaws.com/underline.prod/uploads/markdown_image/1/image/944d6ea6f697f1478d5927dfced2b881.jpg 1) HLN fit of the magnetoconductance and ARPES analysis of a Sb2Te3 film. https://s3.eu-west-1.amazonaws.com/underline.prod/uploads/markdown_image/1/image/dc881fa1b2c83587acbe82b0640f1377.jpg 2) HLN fit of the magnetoconductance and ARPES analysis of aBi2Te3 film.
    • Video
  • CSD 2042221: Experimental Crystal Structure Determination
    Related Article: Santanu Pathak, Parnika Das, Tilak Das, Guruprasad Mandal, Boby Joseph, Manjulata Sahu, S. D. Kaushik, Vasudeva Siruguri|2020|Acta Crystallogr.,Sect.C:Cryst.Struct.Chem.|76|1034|doi:10.1107/S2053229620013960
    • Dataset
  • CSD 2042222: Experimental Crystal Structure Determination
    Related Article: Santanu Pathak, Parnika Das, Tilak Das, Guruprasad Mandal, Boby Joseph, Manjulata Sahu, S. D. Kaushik, Vasudeva Siruguri|2020|Acta Crystallogr.,Sect.C:Cryst.Struct.Chem.|76|1034|doi:10.1107/S2053229620013960
    • Dataset
  • Behind the Scene of “The Holy Family with St. Anne and the Young St. John” by Bernardino Luini: A Computer-Assisted Method to Unveil the Underdrawings
    Uncovering the underdrawings (UDs), the preliminary sketch made by the painter on the grounded preparatory support, is a keystone for understanding the painting's history including the original project of the artist, the pentimenti (an underlying image in a painting providing evidence of revision by the artist) or the possible presence of co-workers’ contributions. The application of infrared reflectography (IRR) has made the dream of discovering the UDs come true: since its introduction, there has been a growing interest in the technology, which therefore has evolved leading to advanced instruments. Most of the literature either report on the technological advances in IRR devices or present case studies, but a straightforward method to improve the visibility of the UDs has not been presented yet. Most of the data handling methods are devoted to a specific painting or they are not user-friendly enough to be applied by non-specialized users, hampering, thus, their widespread application in areas other than the scientific one, e.g., in the art history field. We developed a computer-assisted method, based on principal component analysis (PCA) and image processing, to enhance the visibility of UDs and to support the art-historians and curators’ work. Based on ImageJ/Fiji, one of the most widespread image analysis software, the algorithm is very easy to use and, in principle, can be applied to any multi- or hyper-spectral image data set. In the present paper, after describing the method, we accurately present the extraction of the UD for the panel “The Holy Family with St. Anne and the Young St. John” and for other four paintings by Luini and his workshop paying particular attention to the painting known as “The Child with the Lamb”.
    • Collection
  • sj-pdf-1-asp-10.1177_0003702820949928 - Supplemental material for Behind the Scene of “The Holy Family with St. Anne and the Young St. John” by Bernardino Luini: A Computer-Assisted Method to Unveil the Underdrawings
    Supplemental material, sj-pdf-1-asp-10.1177_0003702820949928 for Behind the Scene of “The Holy Family with St. Anne and the Young St. John” by Bernardino Luini: A Computer-Assisted Method to Unveil the Underdrawings by Michele Caccia, Letizia Bonizzoni, Marco Martini, Raffaella Fontana, Valeria Villa and Anna Galli in Applied Spectroscopy
    • Document
  • CCDC 2016034: Experimental Crystal Structure Determination
    Related Article: Nicola Panza, Armando di Biase, Silvia Rizzato, Emma Gallo, Giorgio Tseberlidis, Alessandro Caselli|2020|Eur.J.Org.Chem.|2020|6635|doi:10.1002/ejoc.202001201
    • Dataset
1