## Publications

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A
Alves, E., J. V. Pinto, R. C. da Silva, M. Peres, M. J. Soares, and T. Monteiro, Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms, vol. 250, pp. 363-367, 2006. AbstractWebsite
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Alves, E., R. C. da Silva, J. V. Pinto, T. Monteiro, B. Savoini, D. Caceres, R. Gonzalez, and Y. Chen, Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms, vol. 206, pp. 148-152, 2003. AbstractWebsite
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Borges, R. P., J. V. Pinto, R. C. da Silva, A. P. Goncalves, M. M. Cruz, and M. Godinho, Journal of Magnetism and Magnetic Materials, vol. 316, issue 2, pp. E191-E194, 2007. AbstractWebsite
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Branquinho, R., B. Veigas, J. V. Pinto, R. Martins, E. Fortunato, and P. V. Baptista, Biosensors & Bioelectronics, vol. 28, issue 1, pp. 44-49, 2011. Abstract
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Branquinho, R., J. V. Pinto, T. Busani, P. Barquinha, L. Pereira, P. V. Baptista, R. Martins, and E. Fortunato, Journal of Display Technology, vol. 9, no. 9, pp. 723–728, 2013. Abstract

The effect of post-deposition annealing temperature on the pH sensitivity of room temperature RF sputtered Ta O was investigated. Structural and morphological features of these films were analyzed before and after annealing at various tem- peratures. The deposited films are amorphous up to 600 Cand crystallize at 700 C in an orthorhombic phase. Electrolyte-insu- lator-semiconductor (EIS) field effect based sensors with an amor- phousTa O sensing layer showed pHsensitivity above 50 mV/pH. For sensors annealed above 200 C pH sensitivity decreased with increasing temperature. Stabilized sensor response andmaximum pHsensitivitywas achieved after low temperature annealing at 200 C, which is compatible with the use of polymeric substrates and application as sensitive layer in oxides TFT-based sensors

Branquinho, R., J. V. Pinto, T. Busani, P. Barquinha, L. Pereira, P. Viana Baptista, R. Martins, and E. Fortunato, Display Technology, Journal of, vol. 9, issue 9, pp. 723-728, 2013. Abstract

The effect of post-deposition annealing temperature on the pH sensitivity of room temperature RF sputtered Ta2O5 was investigated. Structural and morphological features of these films were analyzed before and after annealing at various temperatures. The deposited films are amorphous up to 600 °C and crystallize at 700 °C in an orthorhombic phase. Electrolyte-insulator-semiconductor (EIS) field effect based sensors with an amorphous Ta2O5 sensing layer showed pH sensitivity above 50 mV/pH. For sensors annealed above 200 °C pH sensitivity decreased with increasing temperature. Stabilized sensor response and maximum pH sensitivity was achieved after low temperature annealing at 200 °C, which is compatible with the use of polymeric substrates and application as sensitive layer in oxides TFT-based sensors.

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Casella, C., H. Costantini, a. Lemut, B. Limata, D. Bemmerer, R. Bonetti, C. Broggini, L. Campajola, P. Cocconi, P. Corvisiero, J. Cruz, a. D'Onofrio, a. Formicola, Z. Fülöp, G. Gervino, L. Gialanella, a. Guglielmetti, C. Gustavino, G. Gyurky, a. Loiano, G. Imbriani, P. a. Jesus, M. Junker, P. Musico, a. Ordine, F. Parodi, M. Parolin, J. V. Pinto, P. Prati, J. P. Ribeiro, V. Roca, D. Rogalla, C. Rolfs, M. Romano, C. Rossi-Alvarez, a. Rottura, F. Schuemann, E. Somorjai, F. Strieder, F. Terrasi, H. P. Trautvetter, a. Vomiero, and S. Zavatarelli, Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 489, pp. 160–169, 2002. Abstract

For the study of astrophysically relevant capture reactions in the underground laboratory LUNA a new setup of high sensitivity has been implemented. The setup includes a windowless gas target, a 4$π$ BGO summing crystal, and beam calorimeters. The setup has been recently used to measure the d(p,$\gamma$)3He cross-section for the first time within its solar Gamow peak, i.e. down to 2.5keV c.m. energy. The features of the optimized setup are described. © 2002 Elsevier Science B.V. All rights reserved.

Casella, C., H. Costantini, A. Lemut, B. Limata, D. Bemmerer, R. Bonetti, C. Broggini, L. Campajola, P. Cocconi, P. Corvisiero, J. Cruz, A. D'Onofrio, A. Formicola, Z. Fulop, G. Gervino, L. Gialanella, A. Guglielmetti, C. Gustavino, G. Gyurky, A. Loiano, G. Imbriani, A. P. Jesus, M. Junker, P. Musico, A. Ordine, F. Parodi, M. Parolin, J. V. Pinto, P. Prati, J. P. Ribeiro, V. Roca, D. Rogalla, C. Rolfs, M. Romano, C. Rossi-Alvarez, A. Rottura, F. Schuemann, E. Somorjai, F. Strieder, F. Terrasi, H. P. Trautvetter, A. Vomiero, and S. Zavatarelli, Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment, vol. 489, issue 1-3, pp. 160-169, 2002. AbstractWebsite
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Casella, C., H. Costantini, A. Lemut, B. Limata, R. Bonetti, C. Broggini, L. Campajola, P. Corvisiero, J. Cruz, A. D'Onofrio, A. Formicola, Z. Fulop, G. Gervino, L. Gialanella, A. Guglielmetti, C. Gustavino, G. Gyurky, G. Imbriani, A. P. Jesus, M. Junker, A. Ordine, J. V. Pinto, P. Prati, J. P. Ribeiro, V. Roca, D. Rogalla, C. Rolfs, M. Romano, C. Rossi-Alvarez, F. Scheumann, E. Somorjai, O. Straniero, F. Strieder, F. Terrasi, H. P. Tratuvetter, S. Zavatarelli, and L. Collaboration, Nuclear Physics A, vol. 706, issue 1-2, pp. 203-216, 2002. AbstractWebsite
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Casimiro, M. H., A. G. Silva, J. V. Pinto, A. M. Ramos, J. Vital, and L. M. Ferreira, Radiation Physics and Chemistry, vol. 81, issue 9, pp. 1314-1318, 2012. Abstract
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Ceia, T. F., A. G. Silva, C. S. Ribeiro, J. V. Pinto, M. H. Casimiro, A. M. Ramos, and J. Vital, Catalysis Today, vol. 236, pp. 98-107, 2014. Abstract
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Cruz, M. M., J. V. Pinto, R. C. da Silva, E. Alves, R. Gonzalez, and M. Godinho, Journal of Magnetism and Magnetic Materials, vol. 316, issue 2, pp. E776-E778, 2007. AbstractWebsite
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Cruz, M. M., R. C. Silva, J. V. Pinto, R. P. Borges, N. Franco, and A. Casaca, Journal of Magnetism and Magnetic Materials, vol. 340: Elsevier, pp. 102–108, 2013. AbstractWebsite

The magnetic and electrical properties of Ni implanted single crystalline TiO2 rutile were studied for nominal implanted fluences between 0.5?1017 cm−2 and 2.0?1017 cm−2 with 150 keV energy, corre- sponding to maximum atomic concentrations between 9 at{%} and 27 at{%} at 65 nm depth, in order to study the formation of metallic oriented aggregates. The results indicate that the as implanted crystals exhibit superparamagnetic behavior for the two higher fluences, which is attributed to the formation of nanosized nickel clusters with an average size related with the implanted concentration, while only paramagnetic behavior is observed for the lowest fluence. Annealing at 1073 K induces the aggregation of the implanted nickel and enhances the magnetization in all samples. The associated anisotropic behavior indicates preferred orientations of the nickel aggregates in the rutile lattice consistent with Rutherford backscattering spectrometry—channelling results. Electrical conductivity displays anisotropic behavior but no magnetoresistive effects were detected.

Cruz, M. M., R. C. da Silva, J. V. Pinto, R. G. Gonzalez, E. Alves, and M. Godinho, Journal of Magnetism and Magnetic Materials, vol. 272, pp. 840-842, 2004. AbstractWebsite
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Duarte, P., D. P. Ferreira, T. F. Lopes, J. V. Pinto, I. M. Fonseca, I. Ferreira Machado, and L. F. Vieira Ferreira, Microporous and Mesoporous Materials, vol. 161, pp. 139-147, 2012. Abstract
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Figueiredo, V., J. V. Pinto, J. Deuermeier, R. Barros, E. Alves, R. Martins, and E. Fortunato, Journal of Display Technology, vol. 9, no. 9, pp. 735–740, 2013. Abstract

Thin-films of copper oxide Cu O were produced by thermal oxidation of metallic copper (Cu) at different tempera- tures (150–450 C). The films produced at temperatures of 200, 250 and 300 C showed high Hall motilities of 2.2, 1.9 and 1.6 cm V s , respectively. Single Cu O phases were obtained at 200 Cand its conversion toCuO starts at 250 C. For lower thick- nesses 40 nm, the films oxidized at 250 Cshowed a complete conversion to CuO phase. Successful thin-film transistors (TFTs) were produce by thermal oxidation of a 20 nm Cu film, obtaining p-type Cu O (at 200 C) and CuO (at 250 C) with On/Off ratios of 6 10 and 1 10 , respectively.

Figueiredo, V., J. V. Pinto, J. Deuermeier, R. Barros, E. Alves, R. Martins, and E. Fortunato, Journal of Display Technology, vol. 9, issue 9, pp. 6, 2013. AbstractWebsite
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Figueiredo, V., E. Elangovan, R. Barros, J. V. Pinto, T. Busani, R. Martins, and E. Fortunato, Journal of Display Technology, vol. 8, no. 1, pp. 41–47, 2012. Abstract

Thin-films of copper oxide @Cu OA were sputtered from a metallic copper (Cu) target and studied as a function of oxygen partial pressure @O??A. A metallic Cu film with cubic structure obtained from 0{%} O?? has been transformed to cubic CuPO phase for the increase in O?? to 9{%} but then changed to monoclinic CuO phase (for O?? PS7). The variation in crystallite size (calculated from x-ray diffraction data) was further substantiated by the variation in grain size (surface microstruc- tures). The Cu O films produced with O?? ranging between 9{%} and 75{%} showed p-type behavior, which were successfully applied to produce thin-film transistors.

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Gonçalves, A., J. Resende, A. C. Marques, J. V. Pinto, D. Nunes, A. Marie, R. Gonçalves, L. Pereira, R. Martins, and E. Fortunato, Solar Energy Materials & Solar Cells, vol. 150, pp. 1-9, 2016.
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Kardarian, K., D. Nunes, P. {Maria Sberna}, A. Ginsburg, D. A. Keller, J. {Vaz Pinto}, J. Deuermeier, A. Y. Anderson, A. Zaban, R. Martins, and E. Fortunato, Solar Energy Materials and Solar Cells, vol. 147, pp. 27–36, apr, 2016. AbstractWebsite

Abstract The present work shows the effect of magnesium doping on structural, optoelectrical and electrical properties of Cu2O thin films prepared by spray pyrolysis. The variation in the concentration of Mg shows significant impact on the final thin film properties, whereas the film doped with 0.5 at{%} of Mg exhibited major property improvements in comparison with the undoped thin film and among the other concentrations tested. This condition was further applied for the deposition of an absorber layer in a heterojunction solar cell array with a gradient in thicknesses of active layers to investigate the impact of changing thicknesses on the PV parameters of the solar cell. TiO2 was used as a window layer and the 0.5 at{%} Cu2O doped film as an absorber layer. The produced heterojunction solar cell array was further exposed to a rapid thermal annealing treatment. The I–V measurements show an open circuit voltage of up to 365 mV and a short circuit current density, which is dependent on absorber layer thickness, and reaches to a maximum value of 0.9 mA/cm2.

Kiazadeh, A., D. Salgueiro, R. Branquinho, J. Pinto, H. L. Gomes, P. Barquinha, R. Martins, and E. Fortunato, APL Materials, vol. 3, no. 6, pp. 062804, 2015. AbstractWebsite

In this study, we report solution-processed amorphous zinc tin oxide transistors exhibiting high operational stability under positive gate bias stress, translated by a recoverable threshold voltage shift of about 20{%} of total applied stress voltage. Under vacuum condition, the threshold voltage shift saturates showing that the gate-bias stress is limited by trap exhaustion or balance between trap filling and emptying mechanism. In ambient atmosphere, the threshold voltage shift no longer saturates, stability is degraded and the recovering process is impeded. We suggest that the trapping time during the stress and detrapping time in recovering are affected by oxygen adsorption/desorption processes. The time constants extracted from stretched exponential fitting curves are ≈106 s and 105 s in vacuum and air, respectively.

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Mateus, R., A. P. Jesus, B. Braizinha, J. Cruz, J. V. Pinto, and J. P. Ribeiro, Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms, vol. 190, pp. 117-121, 2002. AbstractWebsite
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Miguel, C., J. V. Pinto, M. Clarke, and M. J. Melo, Dyes and Pigments, vol. 102, pp. 210-217, 2014. AbstractWebsite

Vermilion red, mercury sulphide (α-HgS), was one of the most important reds in art and its use as a pigment dates back to Antiquity. In medieval Europe, it could be mined as cinnabar, or produced as vermilion by heating mercury with sulphur. This work aims to study the production of synthetic vermilion as a medieval pigment and to confirm which was the source (mineral or artificial) of the reds used in Portuguese medieval illuminations. The production of synthetic vermilion was based on the process described in the Judaeo-Portuguese medieval treatise “The book on how to make colours”, using materials and technologies as close as possible to the medieval ones. The reaction mechanism was studied by following the heating process by X-ray diffraction, and it was possible to conclude that the transformation from black cubic β-HgS into red hexagonal α-HgS is a solid-state phase transition, occurring at 235 °C. This result is contrary to what published in technical art literature, in which this process is described as a sublimation. Moreover, Scanning Electron Microscopy evidenced a sinterization effect on the artificial vermilion, not found in medieval original samples nor in paints prepared with mineral cinnabar from Almadén (Spain). Red mercury sulphide, natural and synthetic, was then prepared as a parchment-glue paint and compared to proteinaceous red paints from 12th–13th century miniatures produced in important medieval monasteries, previously fully characterized by a multi-analytical approach (μ-Energy dispersive X-ray fluorescence, μ-Fourier Transform Infrared Spectroscopy, Raman microscopy). A comparative Electron probe microanalysis of the red paints point to a mineral provenance for medieval vermilion found in Portuguese illuminations.

Morais, A. R. C., J. V. Pinto, D. Nunes, L. B. Roseiro, M. C. Oliveira, E. Fortunato, and R. Bogel-Łukasik, ACS Sustainable Chemistry {&} Engineering: American Chemical Society, dec, 2015. AbstractWebsite
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Nandy, S., G. Goncalves, J. V. Pinto, T. Busani, V. Figueiredo, L. Pereira, R. F. Paiva Martins, and E. Fortunato, Nanoscale, vol. 5, issue 23, pp. 11699-11709, 2013. AbstractWebsite

The present work focuses on a qualitative analysis of localised I-V characteristics based on the nanostructure morphology of highly dense arrays of p-type NiO nano-pillars (NiO-NPs). Vertically aligned NiO-NPs have been grown on different substrates by using a glancing angle deposition (GLAD) technique. The preferred orientation of as grown NiO-NPs was controlled by the deposition pressure. The NiO-NPs displayed a polar surface with a microscopic dipole moment along the (111) plane (Tasker's type III). Consequently, the crystal plane dependent surface electron accumulation layer and the lattice disorder at the grain boundary interface showed a non-uniform current distribution throughout the sample surface, demonstrated by a conducting AFM technique (c-AFM). The variation in I-V for different points in a single current distribution grain (CD-grain) has been attributed to the variation of Schottky barrier height (SBH) at the metal-semiconductor (M-S) interface. Furthermore, we observed that the strain produced during the NiO-NPs growth can modulate the SBH. Inbound strain acts as an external field to influence the local electric field at the M-S interface causing a variation in SBH with the NPs orientation. This paper shows that vertical arrays of NiO-NPs are potential candidates for nanoscale devices because they have a great impact on the local current transport mechanism due to its nanostructure morphology.