functionalized zno microbelt as improved co sensor

Abstract Miniaturized gas sensors are increasingly important to monitor the quality of air in a wide range of human environments. Semiconductor metal oxides have proved to be a useful family of materials, in this direction. Unfortunately, metal oxide sensors need a high temperature to respond to any target gas. In order to work around this limit, we fabricate hybrid sensors consisting in single zinc oxide microbelts decorated with organic molecules. Fluorinated tetraphenylporphyrin (H 2 TTPF) is deposited via supersonic molecular beam and considerably improve the performance of the microsensor. The microdevice is investigated with XRD, SEM and AFM techniques. While the as-is ZnO microbelt shows no response up to 150°C, the H 2 TTPF decorated microsensor shows a clear and quick response even at 75°C

Surface plasmon resonance based on molecularly imprinted nanoparticles for the picomolar detection of the iron regulating hormone Hepcidin-25

Molecular modelling

Free-standing graphene oxide and carbon nanotube hybrid papers with enhanced electrical and mechanic performance and their synergy in polymer laminates

Hybrid nanomaterials fabricated by the heterogeneous integration of 1D (carbon nanotubes) and 2D (graphene oxide) nanomaterials showed synergy in electrical and mechanical properties. Here, we reported the infiltration of carboxylic functionalized single-walled carbon nanotubes (C-SWNT) into free-standing graphene oxide (GO) paper for better electrical and mechanical properties than native GO. The stacking arrangement of GO sheets and its alteration in the presence of C-SWNT were comprehensively explored through scanning electron microscopy, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction. The C-SWNTs bridges between different GO sheets produce a pathway for the flow of electrical charges and provide a tougher hybrid system. The nanoscopic surface potential map reveals a higher work function of the individual functionalised SWNTs than surrounded GO sheets showing efficient charge exchange. We observed the enhanced conductivity up to 50 times and capacitance up to 3.5 times of the hybrid structure than the GO-paper. The laminate of polystyrene composites provided higher elastic modulus and mechanical strength when hybrid paper is used, thus paving the way for the exploitation of hybrid filler formulation in designing polymer composites

Experience of accreditation in a surface science laboratory

The analytical laboratory MateC of Fondazione Bruno Kessler has successfully offered material characterization on international research and development market for the last 25 years. Since the beginning, this market has drastically changed becoming more exacting for higher standards, and introducing a quality management system became mandatory for a successful operation. In order to pursue the market and customer needs, the MateC activities have been accredited according to ISO/IEC 17025 quality management standards. This paper summarizes many years’ experience of work under the ISO/IEC 17025 compliant quality system standard in a surface science laboratory for performing material characterizations, considering all significant pros and cons

Surface Characterization of Polydimethylsiloxane: An AFM study

Using Polydimethylsiloxane (PDMS) for flexible electronics is challenging because of its surface properties, leading to cracks and poor adhesion. In this paper, we present a study of plasma treatment on PDMS surface and its effect on modifying the surface properties for metal deposition. We observe that the sinusoidal structure that is formed on PDMS can be controlled by varying the plasma oxidation time and temperature

Dynamic secondary ion mass spectrometry and X-ray photoelectron spectroscopy on artistic bronze and copper artificial patinas

To prevent the natural processes of decay and to develop and improve the treatments of conservation and restoration of artistic bronzes meaning statues and sculptures, it is important understanding the patination processes and the knowledge of artificially corroded surfaces. Chemical and physical characterization of artificial patinas obtained on artistic bronzes and coppers by using the 19th century Western traditional patination techniques and recipes by means of SEM–EDS, light microscopy and ATR/ FT-IR has been done in previous studies [I.Z. Balta, L. Robbiola, Characterization of artificial black patinas on artistic cast bronze and pure copper by using SEM–EDS and light microscopy, in: Proceedings of the 13th European Microscopy Congress, 22–27 August 2004, Antwerp, Belgium, EMC 2004 CD-Rom Conference Preprints; I.Z. Balta, L. Robbiola, Traditional artificial artistic bronze and copper patinas—an investigation by SEM–EDS and ATR/FT-IR, in: Proceedings of the 8th International Conference on Non Destructive Investigations and Microanalysis for the Diagnostics and Conservation of the Cultural and Environmental Heritage, 15–19 May 2005, Lecce, Italy, ART’05 CD-Rom Conference Preprints]. Differences in morphology (structure, thickness, porosity, adherence, compactity, uniformity, homogeneity) and also in composition, on both artistic cast bronze and pure copper patinas, were clearly evidenced. Further in-depth investigation is required to be carried out in order to better understand the patinas mechanisms of formation and the layers kinetics of growth. The elemental and chemical analysis, either on a surface monolayer or in a depth profile, by using the Secondary Ion Mass Spectrometry (SIMS) and X-ray Photoelectron Spectroscopy (XPS) techniques, can provide this kind of information, unique at trace-level sensitivity. SIMS has proved to be a suitable analytical technique for analyzing small amounts of material with high atomic sensitivity (ppm or even ppb) and high depth/ lateral resolution in the micron and sub-micron range [R.G. Wilson, F.A. Stevie, C.W. Magee, Secondary Ion Mass Spectrometry: A Practical Handbook for Depth Profiling and Bulk Impurity Analysis, Wiley & Sons, New York, 1989; M. Dowsett, A. Adriaens, The role of SIMS in cultural heritage studies, Nucl. Instr. Meth. Phys. Res. B 226 (2004) 38–52]. XPS has the ability to provide detailed chemical information on virtually each kind of solid sample, and elemental identification is therefore possible due to the core level photoemission. The most important advantage is the high surface sensitivity of the chemical information (a few monolayers) [E. Ciliberto, G. Spoto, Modern Analytical Methods in Art and Archaeology, John Wiley & Sons, Inc., New York, 2000]. In addition elements’ relative abundance can be made semiquantitative or quantitative and information on chemical bonds can be derived. The aim of the present work is to highlight the advantages and the limits of XPS and Dynamic SIMS surface analytical techniques for the characterization of artistic bronze and copper artificial patinas. The results obtained on the analyzed samples allowed the distribution of themain elements in the corrosion patinas layers and the contribution of each elements present in bronze matrix to the color of the resulting patinas to be precisely revealed. This information could be used for comparative studies between artificial and natural patinas, and also for provenience and authentication studies for artistic and archaeological bronzes

Development of nano-topography during SIMS characterization of Ge1-xSnx alloy

Ge1-xSnx is a semiconductor alloy, compatible with silicon technology, with a bandgap tunable with Sn concentration (3%<x<7% can change the Ge bandgap from indirect to direct) [1], high electron and hole mobility [2,3]. For all those applications, it is mandatory to define analytical approaches able to provide accurate measurements of Sn content. SIMS can be a valuable choice but quantification and matrix issues due to the high Sn content need to be addressed. Therefore, we developed a SIMS protocol using Sn ion implants on Ge as reference samples. Ion implantation was carried out at liquid nitrogen temperature, in order to avoid the well-known phenomenon of Ge nanostructuration under heavy ion implantation at room temperature [4,5]. Implant fluences varied between 1x1014 at/cm2 and 5x1015 at/cm2 and implant energy was set at 45keV. SIMS characterization was performed in different configurations, i.e. using O2+ as primary beam and collecting positive secondary ions, Cs+ and negative secondary ions, Cs+ collecting MCs+ ions; the final results were compared with quantitative measurements obtained by RBS, revealing a good accuracy for the MCs+ protocol. However, it was observed that the applied sputtering conditions (Cs+ 1 keV, 55° incidence vs. normal) induced an early formation of surface topography resulting in a variation of sputtering yield. AFM images will be reported showing the peculiar topography developed on Ge and corrections to improve depth calibration accuracy will be discussed. The obtained protocol was then used to quantify also SIMS profiles of room temperature Sn implants, i.e. nanostructured Ge samples, with good accuracy. [1] S. Gupta et al., IEDM 2011. [2] G. He and H.A. Atwater, Phys. Rev. Lett., 79, (2007), 1937. [3] J.D. Sau and M.L. Cohen, Phys. Rev. B, 75, (2007), 045208. [4] I.H. Wilson, J. Appl. Phys. 53(3), (1982), 1698. [5] N.G. Rudawski and K.C. Jones, J. Mater. Res. 28(13), 1633, 201

Development of nano-topography during SIMS characterization of Ge1-xSnx alloy

none5Ge1-xSnx is a semiconductor alloy, compatible with silicon technology, with a bandgap tunable with Sn concentration (3%<x<7% can change the Ge bandgap from indirect to direct) [1], high electron and hole mobility [2,3]. For all those applications, it is mandatory to define analytical approaches able to provide accurate measurements of Sn content. SIMS can be a valuable choice but quantification and matrix issues due to the high Sn content need to be addressed. Therefore, we developed a SIMS protocol using Sn ion implants on Ge as reference samples. Ion implantation was carried out at liquid nitrogen temperature, in order to avoid the well-known phenomenon of Ge nanostructuration under heavy ion implantation at room temperature [4,5]. Implant fluences varied between 1x10^14 at/cm2 and 5x10^15 at/cm2 and implant energy was set at 45keV. SIMS characterization was performed in different configurations, i.e. using O2+ as primary beam and collecting positive secondary ions, Cs+ and negative secondary ions, Cs+ collecting MCs+ ions; the final results were compared with quantitative measurements obtained by RBS, revealing a good accuracy for the MCs+ protocol. However, it was observed that the applied sputtering conditions (Cs+ 1 keV, 55° incidence vs. normal) induced an early formation of surface topography resulting in a variation of sputtering yield. AFM images will be reported showing the peculiar topography developed on Ge and corrections to improve depth calibration accuracy will be discussed. The obtained protocol was then used to quantify also SIMS profiles of room temperature Sn implants, i.e. nanostructured Ge samples, with good accuracy. [1] S. Gupta et al., IEDM 2011. [2] G. He and H.A. Atwater, Phys. Rev. Lett., 79, (2007), 1937. [3] J.D. Sau and M.L. Cohen, Phys. Rev. B, 75, (2007), 045208. [4] I.H. Wilson, J. Appl. Phys. 53(3), (1982), 1698. [5] N.G. Rudawski and K.C. Jones, J. Mater. Res. 28(13), 1633, 2013M. Secchi; E. Demenev; D. Giubertoni; E. Iacob; M. BersaniM. Secchi; E. Demenev; D. Giubertoni; E. Iacob; M. Bersan