Fabrizio Maseri - Academia.edu (original) (raw)

Papers by Fabrizio Maseri

The Journal of the Acoustical Society of America, 2002

Based on the principle of phononic band gap materials, the control of acoustic frequency gaps by ... more Based on the principle of phononic band gap materials, the control of acoustic frequency gaps by altering the geometry of the system is analyzed in the particular case of a set of parallel solid square-section columns distributed in air on a square lattice. This system is shown to be sensitive enough to the rotation of the columns to be considered for a practical sonic band gap width engineering. For different geometric configurations, experimental and theoretical results are presented and a discussion about the application of such structures as sound insulators is discussed. We acknowledge the use of the Namur Scientific Computing Facility (Namur-SCF), a common project between FNRS, IBM Belgium, and the Facultes Universitaires Notre-Dame de la Paix (FUNDP). [C. Goffaux acknowledges the financial support of the FIRST program of the Walloon Region Government and the Research and Development Centre of Cockerill-Sambre (ARCELOR Group).]

Superhydrophobic surfaces were fabricated with a high water contact angle (CA) of 155° and a low ... more Superhydrophobic surfaces were fabricated with a high water contact angle (CA) of 155° and a low CA hysteresis of 3°. This is achieved by covering the substrate with carbon-based microstructures that take the shape of flowers. These structures, synthesized by pulsed magnetron discharge from acetylene, are confirmed to be fractal by the box-counting determination method. The deposition method is simple,

A design is proposed for a stable infrared source suited to absorbance measurements. The source i... more A design is proposed for a stable infrared source suited to absorbance measurements. The source is a parallelepipedic cavity of tantalum, heated to 2600 K, with an apparent emissivity in excess of0.7. 1t is observed to be three times brighter at 3000 cm-1 than the 1440-K SiC bar. A mode! is constructed in order to estimate the temperature distribution. For this kind of source, the temperature and emissivity are found to be qui te uniform. A comparison between estimated and experimental values of temperature and emissivity is discussed.

Journal of the American Society For Mass Spectrometry, Mar 1, 2010

Thin films deposited on silicon substrate by three different methods of plasma polymerization of ... more Thin films deposited on silicon substrate by three different methods of plasma polymerization of acetylene were analyzed by direct laser desorption/ionization Fourier transform mass spectrometry. High-resolution mass spectra showed the presence of carbon clusters and hydrocarbon oligomers in different relative abundances. During unipolar and continuous discharge polymerization of acetylene-hydrogen gas mixtures, quadrupole mass spectra of the plasma constituents showed the presence of molecular species with m/z lower than 100mainly peaks of C 4 H 2 and C 6 H 2 . Films produced had smooth surfaces and the corresponding LDI-FTMS spectra displayed only carbon cluster signals in the positive ion mode and both hydrocarbon and carbon cluster signals (with much higher relative abundance of carbon cluster signals) in the negative ion mode. Alternatively, during bipolar discharge with either higher acetylene gas flux (Ͼ40 cm 3 /min) or longer deposition times (Ͼ10 min), quadrupole mass spectra of the plasma constituents showed signals corresponding to polycyclic aromatic hydrocarbons (PAH) with m/z higher than 100. SEM pictures of the bipolar thin films demonstrated the presence of "flower" structures and nanoparticles developed on the surface. LDI-FTMS spectra of such thin films showed either total absence or lower relative abundance of carbon cluster signals, compared with hydrocarbon signals. (J Am Soc Mass Spectrom 2010, 21, 411-420)

Corrosion Engineering Science and Technology, 2010

Review of Scientific Instruments, 1993

A design is proposed for a stable infrared source suited to absorbance measurements. The source i... more A design is proposed for a stable infrared source suited to absorbance measurements. The source is a parallelepipedic cavity of tantalum, heated to 2600 K, with an apparent emissivity in excess of 0.7. It is observed to be three times brighter at 3000 cm−1 than the 1440-K SiC bar. A model is constructed in order to estimate the temperature distribution.

Applied Surface Science, 2014

In earlier works, we demonstrated the potential of polysilazane (PSZ) coatings for a use as insul... more In earlier works, we demonstrated the potential of polysilazane (PSZ) coatings for a use as insulating layers in Cu(In,Ga)Se 2 (CIGS) solar cells prepared on steels substrates and showed a good adhesion between PSZ coatings and both AISI316 and AISI430 steels. In the present paper, spectroscopic techniques are used to elucidate the reason of such adhesion. X-ray Photoelectron Spectroscopy (XPS) was used to investigate surfaces for the two steel substrates and showed the presence of metal oxides and metal hydroxides at the top surface. XPS has been also used to probe interfaces between substrates and PSZ, and metallosiloxane (Me-O-Si) covalent bonds have been detected. These results were confirmed by Infra-Red Reflection Absorption Spectroscopy (IRRAS) analyses since vibrations related to Cr-O-Si and Fe-O-Si compounds were detected. Thus, the good adhesion between steel substrates and PSZ coatings was explained by covalent bonding through chemical reactions between PSZ precursors and hydroxide functional groups present on top surface of the two types of steel. Based on these results, an adhesion mechanism between steel substrates and PSZ coatings is proposed.

Time-Resolved Laser Spectroscopy in Biochemistry II, 1990

2011 37th IEEE Photovoltaic Specialists Conference, 2011

For the fabrication of monolithically integrated flexible CIGS modules on stainless steel, indivi... more For the fabrication of monolithically integrated flexible CIGS modules on stainless steel, individual photovoltaic cells must be insulated from the metal substrates by a barrier layer that can sustain high temperature treatment. In this work combination of sol-gel (organosilane-sol) and sputtered SiAlxOy thin layers (TDBL) were prepared on stainless steel substrates. At first, the deposition of organosilane-sol dielectric layers on the commercial AISI-316-2RB stainless steel (Rz = 500 nm, RMS= 56 nm) induces a planarization of the surfaces (RMS = 16.4nm, Rz =176nm). The leakage current in DC mode through the dielectric layers was measured by preparing metal-insulator-metal (MIM) junction that acts as capacitor. This method proposed here allowed us to quantify the quality the quality of our TDBL insulating layer and its lateral uniformity. Indeed, evaluating a ratio of the number of valid MIM capacitors to the number of tested MIM capacitors, a yield of ~ 95% and 50% has been reached respectively with non annealed and annealed samples based sol-gel double layer. A yield of 100% has been reached with reinforced PCDP by sputtered SiAlxOy thin layer showing perfect electrical insulation. Since this yield is obtained on several samples, it can be extrapolated to any substrate size. Furthermore, according to Glow Discharge Optical Emission Spectroscopy (GDOES) measurements, these barrier layers exhibit excellent barrier properties against the diffusion of undesired atoms which could spoil the electronic and optical properties of CIGS based photovoltaic cells.

Thin Solid Films, 2013

For the fabrication of monolithically integrated flexible Cu(In, Ga)Se 2 , CIGS modules on stainl... more For the fabrication of monolithically integrated flexible Cu(In, Ga)Se 2 , CIGS modules on stainless steel, individual photovoltaic cells must be insulated from metal substrates by a barrier layer that can sustain high thermal treatments. In this work, a combination of sol-gel (organosilane-sol) and sputtered SiAlxOy forming thin diffusion barrier layers (TDBL) was prepared on stainless steel substrates. The deposition of organosilane-sol dielectric layers on the commercial stainless steel (maximal roughness, Rz = 500 nm and Root Mean Square roughness, RMS = 56 nm) induces a planarization of the surface (RMS = 16.4 nm, Rz = 176 nm). The DC leakage current through the dielectric layers was measured for the metal-insulator-metal (MIM) junctions that act as capacitors. This method allowed us to assess the quality of our TDBL insulating layer and its lateral uniformity. Indeed, evaluating a ratio of the number of valid MIM capacitors to the number of tested MIM capacitors, a yield of~95% and 50% has been reached respectively with non-annealed and annealed samples based on sol-gel double layers. A yield of 100% was achieved for sol-gel double layers reinforced with a sputtered SiAlxOy coating and a third sol-gel monolayer. Since this yield is obtained on several samples, it can be extrapolated to any substrate size. Furthermore, according to Glow Discharge Optical Emission Spectroscopy and Time of Flight Secondary Ion Mass Spectroscopy measurements, these barrier layers exhibit excellent barrier properties against the diffusion of undesired atoms which could otherwise spoil the electronic and optical properties of CIGS photovoltaic cells.

Thin Solid Films, 2013

Molybdenum films are investigated on stainless steel substrates coated with polysilazane based so... more Molybdenum films are investigated on stainless steel substrates coated with polysilazane based sol-gel and SiO x layers for flexible CIGS solar cell applications. Thermal stability of the multilayer has been studied. The thickness of polysilazane films are significantly reduced (17%) after heat treatment suggesting a thermal degradation. Four different microstructures were found for Mo films by varying argon total pressure from 2.6×10 −1 Pa to 2.6 Pa. It was shown that continuous films, low sheet resistance (0.5 Ω/□) and well facetted grains can be achieved when Mo films are deposited on heated substrates at homologous temperature, T of 0.2.

Surface and Coatings Technology, 2011

Superhydrophobic surfaces were fabricated with a high water contact angle (CA) of 155° and a low ... more Superhydrophobic surfaces were fabricated with a high water contact angle (CA) of 155° and a low CA hysteresis of 3°. This is achieved by covering the substrate with carbon-based microstructures that take the shape of flowers. These structures, synthesized by pulsed magnetron discharge from acetylene, are confirmed to be fractal by the box-counting determination method. The deposition method is simple,

Plasma Processes and Polymers, 2009

Langmuir, 2011

The growth of hydrogenated amorphous carbons (a-C:H) produced by continuous or pulsed discharges ... more The growth of hydrogenated amorphous carbons (a-C:H) produced by continuous or pulsed discharges of acetylene (C(2)H(2)) in an unbalanced magnetron setup was investigated. At 5 × 10(-3) Torr, only smooth films are obtained, whereas at 5 × 10(-1) Torr using a pulsed discharge some microtextured films are formed if the duty cycle is low. The morphology of these microtextured films consists of nanoparticles, filamentary particles, and particular agglomerates ("microflowers"). This paper presents a study of acetylene gas phase polymerization by mass spectrometry, and a detailed analysis of bulk structure of films by combining three techniques which include IR spectroscopy, Raman spectroscopy, and laser desorption/ionization Fourier transform mass spectrometry (LDI-FTMS). Finally, based on the study of gas phase and film structure, we propose a model for the growth of both smooth and microtextured films.

Journal of Physics D: Applied Physics, 1991

The apparent emissivity of a parallelepipedic hollow radiation source is computed to all orders o... more The apparent emissivity of a parallelepipedic hollow radiation source is computed to all orders of multiple reflection. An iterative method is used to solve accurately the apparent emissivity integral equation, and a special discretization scheme is constructed to handle exactly all geometrical factors. Explicit expressions are given which allow the difficulties associated with the singularities appearing near the cavity edges

Journal of Physics: Conference Series, 2013

High quality Aluminium-doped Zinc Oxide (AZO) films have been obtained by suitably controlling th... more High quality Aluminium-doped Zinc Oxide (AZO) films have been obtained by suitably controlling the magnetron sputtering parameters and the substrate temperature. The Xray diffraction studies showed that a transition of orientation from (002) plane to (103) plane, versus substrate temperature. The surface morphology characterized by scanning electron microscopy and atomic force microscopy exhibited a dense and compact structure at higher temperature. For 200 nm thick AZO films deposited at temperature 530°C, using a ZnO target with an Al 2 O 3 content of 3 wt%, the lowest electrical resistivity is 6.810 -4 .cm and transmittance is over 85% in the visible spectral region. The conductivity improvement of AZO films was closely related to the crystallanity characterized by the (103) orientation and the densely packed structure.

The Journal of the Acoustical Society of America, 2002

Based on the principle of phononic band gap materials, the control of acoustic frequency gaps by ... more Based on the principle of phononic band gap materials, the control of acoustic frequency gaps by altering the geometry of the system is analyzed in the particular case of a set of parallel solid square-section columns distributed in air on a square lattice. This system is shown to be sensitive enough to the rotation of the columns to be considered for a practical sonic band gap width engineering. For different geometric configurations, experimental and theoretical results are presented and a discussion about the application of such structures as sound insulators is discussed. We acknowledge the use of the Namur Scientific Computing Facility (Namur-SCF), a common project between FNRS, IBM Belgium, and the Facultes Universitaires Notre-Dame de la Paix (FUNDP). [C. Goffaux acknowledges the financial support of the FIRST program of the Walloon Region Government and the Research and Development Centre of Cockerill-Sambre (ARCELOR Group).]

Superhydrophobic surfaces were fabricated with a high water contact angle (CA) of 155° and a low ... more Superhydrophobic surfaces were fabricated with a high water contact angle (CA) of 155° and a low CA hysteresis of 3°. This is achieved by covering the substrate with carbon-based microstructures that take the shape of flowers. These structures, synthesized by pulsed magnetron discharge from acetylene, are confirmed to be fractal by the box-counting determination method. The deposition method is simple,

A design is proposed for a stable infrared source suited to absorbance measurements. The source i... more A design is proposed for a stable infrared source suited to absorbance measurements. The source is a parallelepipedic cavity of tantalum, heated to 2600 K, with an apparent emissivity in excess of0.7. 1t is observed to be three times brighter at 3000 cm-1 than the 1440-K SiC bar. A mode! is constructed in order to estimate the temperature distribution. For this kind of source, the temperature and emissivity are found to be qui te uniform. A comparison between estimated and experimental values of temperature and emissivity is discussed.

Journal of the American Society For Mass Spectrometry, Mar 1, 2010

Thin films deposited on silicon substrate by three different methods of plasma polymerization of ... more Thin films deposited on silicon substrate by three different methods of plasma polymerization of acetylene were analyzed by direct laser desorption/ionization Fourier transform mass spectrometry. High-resolution mass spectra showed the presence of carbon clusters and hydrocarbon oligomers in different relative abundances. During unipolar and continuous discharge polymerization of acetylene-hydrogen gas mixtures, quadrupole mass spectra of the plasma constituents showed the presence of molecular species with m/z lower than 100mainly peaks of C 4 H 2 and C 6 H 2 . Films produced had smooth surfaces and the corresponding LDI-FTMS spectra displayed only carbon cluster signals in the positive ion mode and both hydrocarbon and carbon cluster signals (with much higher relative abundance of carbon cluster signals) in the negative ion mode. Alternatively, during bipolar discharge with either higher acetylene gas flux (Ͼ40 cm 3 /min) or longer deposition times (Ͼ10 min), quadrupole mass spectra of the plasma constituents showed signals corresponding to polycyclic aromatic hydrocarbons (PAH) with m/z higher than 100. SEM pictures of the bipolar thin films demonstrated the presence of "flower" structures and nanoparticles developed on the surface. LDI-FTMS spectra of such thin films showed either total absence or lower relative abundance of carbon cluster signals, compared with hydrocarbon signals. (J Am Soc Mass Spectrom 2010, 21, 411-420)

Corrosion Engineering Science and Technology, 2010

Review of Scientific Instruments, 1993

A design is proposed for a stable infrared source suited to absorbance measurements. The source i... more A design is proposed for a stable infrared source suited to absorbance measurements. The source is a parallelepipedic cavity of tantalum, heated to 2600 K, with an apparent emissivity in excess of 0.7. It is observed to be three times brighter at 3000 cm−1 than the 1440-K SiC bar. A model is constructed in order to estimate the temperature distribution.

Applied Surface Science, 2014

In earlier works, we demonstrated the potential of polysilazane (PSZ) coatings for a use as insul... more In earlier works, we demonstrated the potential of polysilazane (PSZ) coatings for a use as insulating layers in Cu(In,Ga)Se 2 (CIGS) solar cells prepared on steels substrates and showed a good adhesion between PSZ coatings and both AISI316 and AISI430 steels. In the present paper, spectroscopic techniques are used to elucidate the reason of such adhesion. X-ray Photoelectron Spectroscopy (XPS) was used to investigate surfaces for the two steel substrates and showed the presence of metal oxides and metal hydroxides at the top surface. XPS has been also used to probe interfaces between substrates and PSZ, and metallosiloxane (Me-O-Si) covalent bonds have been detected. These results were confirmed by Infra-Red Reflection Absorption Spectroscopy (IRRAS) analyses since vibrations related to Cr-O-Si and Fe-O-Si compounds were detected. Thus, the good adhesion between steel substrates and PSZ coatings was explained by covalent bonding through chemical reactions between PSZ precursors and hydroxide functional groups present on top surface of the two types of steel. Based on these results, an adhesion mechanism between steel substrates and PSZ coatings is proposed.

Time-Resolved Laser Spectroscopy in Biochemistry II, 1990

2011 37th IEEE Photovoltaic Specialists Conference, 2011

For the fabrication of monolithically integrated flexible CIGS modules on stainless steel, indivi... more For the fabrication of monolithically integrated flexible CIGS modules on stainless steel, individual photovoltaic cells must be insulated from the metal substrates by a barrier layer that can sustain high temperature treatment. In this work combination of sol-gel (organosilane-sol) and sputtered SiAlxOy thin layers (TDBL) were prepared on stainless steel substrates. At first, the deposition of organosilane-sol dielectric layers on the commercial AISI-316-2RB stainless steel (Rz = 500 nm, RMS= 56 nm) induces a planarization of the surfaces (RMS = 16.4nm, Rz =176nm). The leakage current in DC mode through the dielectric layers was measured by preparing metal-insulator-metal (MIM) junction that acts as capacitor. This method proposed here allowed us to quantify the quality the quality of our TDBL insulating layer and its lateral uniformity. Indeed, evaluating a ratio of the number of valid MIM capacitors to the number of tested MIM capacitors, a yield of ~ 95% and 50% has been reached respectively with non annealed and annealed samples based sol-gel double layer. A yield of 100% has been reached with reinforced PCDP by sputtered SiAlxOy thin layer showing perfect electrical insulation. Since this yield is obtained on several samples, it can be extrapolated to any substrate size. Furthermore, according to Glow Discharge Optical Emission Spectroscopy (GDOES) measurements, these barrier layers exhibit excellent barrier properties against the diffusion of undesired atoms which could spoil the electronic and optical properties of CIGS based photovoltaic cells.

Thin Solid Films, 2013

For the fabrication of monolithically integrated flexible Cu(In, Ga)Se 2 , CIGS modules on stainl... more For the fabrication of monolithically integrated flexible Cu(In, Ga)Se 2 , CIGS modules on stainless steel, individual photovoltaic cells must be insulated from metal substrates by a barrier layer that can sustain high thermal treatments. In this work, a combination of sol-gel (organosilane-sol) and sputtered SiAlxOy forming thin diffusion barrier layers (TDBL) was prepared on stainless steel substrates. The deposition of organosilane-sol dielectric layers on the commercial stainless steel (maximal roughness, Rz = 500 nm and Root Mean Square roughness, RMS = 56 nm) induces a planarization of the surface (RMS = 16.4 nm, Rz = 176 nm). The DC leakage current through the dielectric layers was measured for the metal-insulator-metal (MIM) junctions that act as capacitors. This method allowed us to assess the quality of our TDBL insulating layer and its lateral uniformity. Indeed, evaluating a ratio of the number of valid MIM capacitors to the number of tested MIM capacitors, a yield of~95% and 50% has been reached respectively with non-annealed and annealed samples based on sol-gel double layers. A yield of 100% was achieved for sol-gel double layers reinforced with a sputtered SiAlxOy coating and a third sol-gel monolayer. Since this yield is obtained on several samples, it can be extrapolated to any substrate size. Furthermore, according to Glow Discharge Optical Emission Spectroscopy and Time of Flight Secondary Ion Mass Spectroscopy measurements, these barrier layers exhibit excellent barrier properties against the diffusion of undesired atoms which could otherwise spoil the electronic and optical properties of CIGS photovoltaic cells.

Thin Solid Films, 2013

Molybdenum films are investigated on stainless steel substrates coated with polysilazane based so... more Molybdenum films are investigated on stainless steel substrates coated with polysilazane based sol-gel and SiO x layers for flexible CIGS solar cell applications. Thermal stability of the multilayer has been studied. The thickness of polysilazane films are significantly reduced (17%) after heat treatment suggesting a thermal degradation. Four different microstructures were found for Mo films by varying argon total pressure from 2.6×10 −1 Pa to 2.6 Pa. It was shown that continuous films, low sheet resistance (0.5 Ω/□) and well facetted grains can be achieved when Mo films are deposited on heated substrates at homologous temperature, T of 0.2.

Surface and Coatings Technology, 2011

Superhydrophobic surfaces were fabricated with a high water contact angle (CA) of 155° and a low ... more Superhydrophobic surfaces were fabricated with a high water contact angle (CA) of 155° and a low CA hysteresis of 3°. This is achieved by covering the substrate with carbon-based microstructures that take the shape of flowers. These structures, synthesized by pulsed magnetron discharge from acetylene, are confirmed to be fractal by the box-counting determination method. The deposition method is simple,

Plasma Processes and Polymers, 2009

Langmuir, 2011

The growth of hydrogenated amorphous carbons (a-C:H) produced by continuous or pulsed discharges ... more The growth of hydrogenated amorphous carbons (a-C:H) produced by continuous or pulsed discharges of acetylene (C(2)H(2)) in an unbalanced magnetron setup was investigated. At 5 × 10(-3) Torr, only smooth films are obtained, whereas at 5 × 10(-1) Torr using a pulsed discharge some microtextured films are formed if the duty cycle is low. The morphology of these microtextured films consists of nanoparticles, filamentary particles, and particular agglomerates ("microflowers"). This paper presents a study of acetylene gas phase polymerization by mass spectrometry, and a detailed analysis of bulk structure of films by combining three techniques which include IR spectroscopy, Raman spectroscopy, and laser desorption/ionization Fourier transform mass spectrometry (LDI-FTMS). Finally, based on the study of gas phase and film structure, we propose a model for the growth of both smooth and microtextured films.

Journal of Physics D: Applied Physics, 1991

The apparent emissivity of a parallelepipedic hollow radiation source is computed to all orders o... more The apparent emissivity of a parallelepipedic hollow radiation source is computed to all orders of multiple reflection. An iterative method is used to solve accurately the apparent emissivity integral equation, and a special discretization scheme is constructed to handle exactly all geometrical factors. Explicit expressions are given which allow the difficulties associated with the singularities appearing near the cavity edges

Journal of Physics: Conference Series, 2013

High quality Aluminium-doped Zinc Oxide (AZO) films have been obtained by suitably controlling th... more High quality Aluminium-doped Zinc Oxide (AZO) films have been obtained by suitably controlling the magnetron sputtering parameters and the substrate temperature. The Xray diffraction studies showed that a transition of orientation from (002) plane to (103) plane, versus substrate temperature. The surface morphology characterized by scanning electron microscopy and atomic force microscopy exhibited a dense and compact structure at higher temperature. For 200 nm thick AZO films deposited at temperature 530°C, using a ZnO target with an Al 2 O 3 content of 3 wt%, the lowest electrical resistivity is 6.810 -4 .cm and transmittance is over 85% in the visible spectral region. The conductivity improvement of AZO films was closely related to the crystallanity characterized by the (103) orientation and the densely packed structure.