Rosendo Sanjines | Ecole Polytechnique Federale de Lausanne (original) (raw)

Papers by Rosendo Sanjines

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1995

We demonstrated that polycrystalline cesium iodide (01) on large area Ni/Au coated printed board ... more We demonstrated that polycrystalline cesium iodide (01) on large area Ni/Au coated printed board provides a quantum efficiency (QE) higher by a factor of 2 than the films deposited on the standard Cu/Au printed circuits. This is the most important result of the present systematic study of the QE lateral inhomogeneity for CsI on different substrates. We found a strong correlation between the QE lateral variation and the morphological homogeneity of the films. The QE was measured by UV photoelectron emission microscopy and spatially resolved X-ray photoemission, and the morphology studies were performed by secondary electron microscopy, X-ray diffraction and scanning tunneling microscopy.

RSC Advances, 2015

The first evidence for the synthesis of a uniform, adhesive polyethylene–FeOx (PE–FeOx) surface l... more The first evidence for the synthesis of a uniform, adhesive polyethylene–FeOx (PE–FeOx) surface leading efficiently to bacterial inactivation is addressed in this study.

Applied Catalysis B: Environmental, 2018

ZnO-films although the conduction band potential energy position of the two semiconductors were i... more ZnO-films although the conduction band potential energy position of the two semiconductors were iso-energetic. By X-ray photoelectron spectroscopy (XPS), Cu2O was identified as the predominant Cu-oxidation state in the sputtered film. A mechanism for the NFX degradation is suggested in which the holes generated by Cu2O transfer to ZnO in the ZnO(n)/CuO(p) in the hetero-junction. This transfer is favored by the electrostatic interaction between both semiconductors. The catalyst optical properties and surface potential were monitored during NFX degradation. Stable repetitive NFX degradation kinetics was observed under visible light on the sputtered ZnO/CuxO films. The use of appropriate scavengers allowed the identification of the intermediate radical species (ROS). XPS analysis provided the proof for redox catalysis taking place within the time of NFX abatement. The application of ZnO/CuxO films in a photo-reactor for the degradation of emerging pollutants seems feasible due to the low cost of Zn and Cu and the fast kinetics found for NFX degradation.

... From energy-resolved mass spectrometry, the nature and energy distributions of positive and n... more ... From energy-resolved mass spectrometry, the nature and energy distributions of positive and negative ions impinging on the surface of a growing TiO 2 film were investigated as a function of the total pressure P T . The thin films were deposited by DC reactive magnetron ...

Surface and Coatings Technology, 2016

Nb1 - xTixNy thin films (with 0 <= x <= 1 and 0.85 <= y <= 1.15) were deposited from ... more Nb1 - xTixNy thin films (with 0 <= x <= 1 and 0.85 <= y <= 1.15) were deposited from Nb and Ti metallic targets using a hybrid process combining high-power impulse magnetron sputtering (HiPIMS) and DC magnetron sputtering (DCMS) techniques. Two series of Nb1-xTixNy films were deposited in which the HiPIMS mode was applied either to the Nb or to the Ti target while the second target (Ti or Nb) was operated in DCMS mode. The HiPIMS generator was operated at a fixed time-average power of 100 W (5 W cm(-2)) with a pulse-width of 50 mu s and a repetition frequency of 1000 Hz whereas the DC power applied to the second target was varied from 0 to 90 W to adjust the relative contents of Ti or Nb in the films. Depositions were performed in an Ar + N-2 atmosphere at a total pressure of 0.5 Pa. The substrate temperature was fixed at 250 degrees C and the sample holder was biased at -50 V. The films were characterized by XRD, SEM, EDS, nanoindentation, optical and electrical measurements. All the ternary films crystallize in the fcc NaCl-type of the structure. The films exhibit a dense columnar structure and their hardness values increase from 26 for TiN to 35 GPa for NbN. The optical properties of the Nb1 - xTixNy films progressively evolve from those of the fcc-NbN to those of the fcc-TiN as the Ti content x increases from 0 to 1. The room temperature resistivity value decreases from about 300 mu Omega cm (for NbN0.99) down to 25 mu Omega cm (for TiN0.98) as x increases from 0 to 1. In contrast to that, Nb1 - xTixNy films deposited under similar deposition conditions using DCMS exhibit open columnar structure, low hardness values (15 to 22 GPa), high electrical resistivity in the range of 200-360 mu Omega cm, and optical properties without clear correlation with the chemical composition of the films. The peculiar physical properties of these films, compared with those obtained by the hybrid process, are mainly attributed to their open columnar morphology. (C) 2015 Elsevier B.V. All rights reserved.

Thin Solid Films, 2019

The present paper reports on an experimental investigation of the structural, electrical and opti... more The present paper reports on an experimental investigation of the structural, electrical and optical properties of Ru rich Ru 1-x Ti x O 2 thin films. Rutile single-phase Ru 1-x Ti x O 2 thin films have been deposited by reactive hybrid High-power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) at a substrate temperature of 250°C. The HiPIMS source was applied to the Ru target while the DCMS source was connected to the Ti target in order to vary the Ti content in the films. The films are well crystallized and compact with randomly orientated nanocrystallites. The optical properties have been investigated by ellipsometric measurements in the optical energy range from 1.3 eV to 3.3 eV, while the electrical resistivity has been measured in the Van der Paw configuration at room temperature. The electrical resistivity increases gradually from 70 μΩcm for pure RuO 2 to about 243 μΩcm for Ru 1-x Ti x O 2 films with x = 0.13. The optical properties are correlated with the Ti doping. The refractive index n changes from a strong dispersion relationship to a moderate one with increasing Ti content. The Ru 1-x Ti x O 2 thin films have been deposited by reactive hybrid

2018 20th International Conference on Transparent Optical Networks (ICTON), 2018

Single photon technology is enabling for quantum communication and processing. Combining single p... more Single photon technology is enabling for quantum communication and processing. Combining single photon sources, routing circuitry and highly efficient detectors in a high yield, low-loss and scalable fashion represent today a major challenge. Nanophotonic devices allow for the realization of on-chip small footprint architectures for generating, manipulating and detecting single photons. Waveguide-integrated superconducting nanowire single photon detectors are today state-of-the art devices capable of detecting single photons propagating in an integrated photonic circuit with high efficiency, speed and low timing uncertainty. Their excellent metrics in the near-infrared allows to directly interface on-chip devices with existing C-Band communication technology systems. To move towards high communication speed, efficient detectors able to sustain Gcps count rate are desirable. Here we present the design process and the experimental characterization of a new generation of fast detectors, consisting of µm-long NbN superconducting nanowires embedded in a SOI two-dimensional photonic crystal cavity. Almost 70% efficiency at telecommunication wavelengths has been achieved with negligible dark counts and sub-ns recovery time, which could enable Gcps count rates.

RSC Advances, 2015

This study reports the photosensitizing effect/mechanism of FeOx under visible light irradiation ... more This study reports the photosensitizing effect/mechanism of FeOx under visible light irradiation and charge transfer to TiO2 on FeOx–TiO2 cosputtered film.

Applied Catalysis B: Environmental, 2016

Co-sputtered TiO 2-Cu polyester (TiO 2-Cu-PES) under actinic light induced bacterial reduction of... more Co-sputtered TiO 2-Cu polyester (TiO 2-Cu-PES) under actinic light induced bacterial reduction of Escherichia coli in the presence of O 2 (air) and under anaerobic conditions. The bacterial inactivation/oxidation proceeds in the absence of O 2 (air) probably due to the highly oxidative TiO 2 vb(h +) species and the toxic Cu present. By the choice of suitable scavengers, the presence of highly oxidative radicals was confirmed in aerobic media. The E. coli inactivation in aerobic media proceeds on TiO 2-Cu-PES within ∼30 min and with a slower kinetics of ∼90 min in anaerobic media. Malondialdehyde generation a product of bacterial inactivation, was observed on the TiO 2-Cu-PES in air and in lesser amounts under anaerobic conditions. Repetitive bacterial inactivation cycles show a Cu-release of ∼2 ppb/cm 2 by the TiO 2-Cu-PES surface as determined by inductively coupled plasma mass spectrometry (IPC-MS). The Cu released is far below the values reported for the Cu released by TiO 2-Cu-PES samples by sputtering Ti and Cu in sequential order from two targets. By X-ray photoelectron spectroscopy (XPS), redox catalysis by the Cu and TiO 2-species was observed under anaerobic conditions providing further evidence for processes leading to bacterial inactivation in anaerobic media. A mechanism for the TiO 2-Cu-PES bacterial inactivation is suggested consistent with the results reported in this study.

Applied Catalysis A: General, 2015

The kinetics of bacterial reduction of Staphylococcus aureus (MRSA) on co-sputtered TiO 2 /Cu-pol... more The kinetics of bacterial reduction of Staphylococcus aureus (MRSA) on co-sputtered TiO 2 /Cu-polyester (TiO 2 /Cu-PES) was found to be little dependent on the applied light dose. But in the case of Escherichia coli, the bacterial reduction kinetics was observed to be strongly dependent on the applied light dose. The reasons for the different effect of the applied light dose on the bacterial reduction are discussed. Mechanistic considerations are suggested to account for this observation. TiO 2 /Cu-PES obtained by direct current magnetron co-sputtering and the bacterial reduction features compared to PES sputtered individually by TiO 2 and Cu. This study presents the first evidence for the stabilizing effect of TiO 2 on the amounts of the Cu released during bacterial inactivation by co-sputtered surfaces compared to sequential sputtering of Ti and/or Cu on PES. The release of Cu-monitored in the ppb range by inductively coupled plasma-mass spectrometry (ICP-MS) is indicative of an oligodynamic effect leading to bacterial reduction. The bacterial reduction of MRSA ATCC 43300 on co-sputtered TiO 2 /Cu led to a 5 log 10 (99.999%) reduction within 120 min in the dark and 60 min under low intensity actinic light. Diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM) and X-ray fluorescence (XRF) describe the TiO 2 /Cu surfaces investigated in this study.

MRS Proceedings, 2005

AlN/TiN multilayered thin films with layer thickness ranging from 1 nm to 50 nm were synthesized ... more AlN/TiN multilayered thin films with layer thickness ranging from 1 nm to 50 nm were synthesized using rf magnetron sputtering at 400°C. Two series of samples were prepared at the substrate bias of Vb = −25 V and −100 V to modify growth texture of individual layers and verify its influence on the formation of coherent structures. XRD and TEM observations showed that in large period films (tc ≥ 30 nm) each constituent grows under its own kinetic, leading to the formation of nano-crysatlline film randomly oriented with no pronounced texture. Decreasing progressively the layer thickness favours the alignment of (0002) basal plane of w-AlN on (111) plane of TiN, and results in development of strong (111) texture, prerequisite for stabilisation of c-AlN and the formation of epitaxial coherent structures. The degree of crystallographic coherence was found to be higher in TiN(111) oriented films than for TiN(002) textured films. The increase of hardness coincides with the structure transit...

Surface and Coatings Technology, 2001

Journal of Applied Physics, 2009

WC/amorphous carbon (a-C) thin films were deposited by dual magnetron sputtering from individual ... more WC/amorphous carbon (a-C) thin films were deposited by dual magnetron sputtering from individual WC and graphite targets. The influence of film composition and microstructure on the optical and electrical properties was investigated. As evidenced by x-ray photoelectron spectroscopy and grazing angle x-ray diffraction measurements, the WC/a-C films are composite materials made of hexagonal W2C and/or cubic β-WC1−X nanocrystallites embedded in

Applied Catalysis B: Environmental, 2016

Insight is provided in this study for the effect of the TiO 2 film densification/compactness on p... more Insight is provided in this study for the effect of the TiO 2 film densification/compactness on polyethylene (PE-TiO 2) by sputtering TiO 2 at two very different energy levels. Uniform, adhesive low energy films were prepared by direct current magnetron sputtering (DCMS) and compared with films sputtered at high energy levels by high power impulse magnetron sputtering (HIPIMS). Nano-particulate TiO 2 films sputtered by HPIMS presented sizes of ∼10.2 nm compared to films sputtered by DCMS with TiO 2 sizes of ∼16.5 nm as determined by X-ray diffraction (XRD). The E. coli inactivation kinetics was three times faster for the samples sputtered by HIPIMS compared to their DCMS counterparts. This is an unexpected finding since the DCMS presenting larger TiO 2 sized nanoparticles released a higher amount of Ti-ions compared to the HIPIMS samples as monitored by inductively coupled plasma mass-spectrometry (ICP-MS). The Ti-ions released do not seem to react through an oligodynamic effect but diffuse through the less compact TiO 2 sputtered by DCMS. The faster bacterial inactivation kinetics observed by the HIPIMS sputtered samples can be understood in terms of the complete of Ti 4+ /Ti 3+ redox conversion during bacterial inactivation detected by X-ray photo-electron spectroscopy (XPS) compared to the smaller Ti 4+ /Ti 3+ effect observed in the DCMS-samples. A higher optical density was detected for the HIPIMS sputtered samples by diffuse reflectance spectroscopy (DRS). Evidence is presented for the shift in surface potential and local pH during bacterial inactivation under aerobic and anaerobic conditions. A reaction mechanism is suggested based on the findings described in this study. The sputtered films present the potential to hinder biofilm formation on flexible thin polymers/textiles widely used in hospitals and health facilities.

Thin Solid Films, 2001

Boron nitride films deposited by ion beam assisted deposition (IBAD) and triode sputtering system... more Boron nitride films deposited by ion beam assisted deposition (IBAD) and triode sputtering system are studied. The presence of the cubic phase was checked by transmission infrared spectroscopy. The adhesion of the films was very poor, the films delaminated just after deposition. In an attempt to improve the adhesion, the deposition conditions (ion energy and flux) were changed after the

Applied Catalysis B: Environmental, 2016

Uniform adhesive TiO 2-ZrO 2 films co-sputtered on polyester (PES) under low intensity sunlight i... more Uniform adhesive TiO 2-ZrO 2 films co-sputtered on polyester (PES) under low intensity sunlight irradiation discolored methylene blue (MB) within 120 min. The discoloration kinetics was seen to be accelerated by a factor four by TiO 2-ZrO 2-Cu containing ∼0.01% Cu, as determined by X-ray fluorescence (XRF). TiO 2-ZrO 2-Cu also increased also accelerated by a factor the discoloration of MB compared to TiO 2 /Cu(PES). MB discoloration was also monitored under visible light in the solar cavity by using a 400 nm cutoff filter. Photocatalyst surfaces were characterized by spectroscopic methods showing the film optical absorption and by X-ray photoelectron spectroscopy (XPS), the surface atomic percentage concentration up to 120 nm (∼600 layers). The band-gaps of TiO 2-ZrO 2 and TiO 2-ZrO 2-Cu were estimated for films co-sputtered for different times. By Fourier transform attenuated infrared spectroscopy (ATR-FTIR), the systematic shift of the predominating s (CH 2) vibration-rotational MB bands was monitored up to complete MB discoloration under low intensity solar simulated light. Evidence is presented for the OH • generation by TiO 2-ZrO 2-Cu participating in the self-cleaning mechanism. The photo-induced interfacial charge transfer (IFCT) on the TiO 2-ZrO 2-Cu is discussed in terms of the electronic band positions of the binary oxides and Cu intra-gap states. This study presents the first evidence for a Cu-promoted composed of two binary oxide semiconductors accelerating the self-cleaning performance.

DOI to the publisher's website. • The final author version and the galley proof are versions of t... more DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1995

We demonstrated that polycrystalline cesium iodide (01) on large area Ni/Au coated printed board ... more We demonstrated that polycrystalline cesium iodide (01) on large area Ni/Au coated printed board provides a quantum efficiency (QE) higher by a factor of 2 than the films deposited on the standard Cu/Au printed circuits. This is the most important result of the present systematic study of the QE lateral inhomogeneity for CsI on different substrates. We found a strong correlation between the QE lateral variation and the morphological homogeneity of the films. The QE was measured by UV photoelectron emission microscopy and spatially resolved X-ray photoemission, and the morphology studies were performed by secondary electron microscopy, X-ray diffraction and scanning tunneling microscopy.

RSC Advances, 2015

The first evidence for the synthesis of a uniform, adhesive polyethylene–FeOx (PE–FeOx) surface l... more The first evidence for the synthesis of a uniform, adhesive polyethylene–FeOx (PE–FeOx) surface leading efficiently to bacterial inactivation is addressed in this study.

Applied Catalysis B: Environmental, 2018

ZnO-films although the conduction band potential energy position of the two semiconductors were i... more ZnO-films although the conduction band potential energy position of the two semiconductors were iso-energetic. By X-ray photoelectron spectroscopy (XPS), Cu2O was identified as the predominant Cu-oxidation state in the sputtered film. A mechanism for the NFX degradation is suggested in which the holes generated by Cu2O transfer to ZnO in the ZnO(n)/CuO(p) in the hetero-junction. This transfer is favored by the electrostatic interaction between both semiconductors. The catalyst optical properties and surface potential were monitored during NFX degradation. Stable repetitive NFX degradation kinetics was observed under visible light on the sputtered ZnO/CuxO films. The use of appropriate scavengers allowed the identification of the intermediate radical species (ROS). XPS analysis provided the proof for redox catalysis taking place within the time of NFX abatement. The application of ZnO/CuxO films in a photo-reactor for the degradation of emerging pollutants seems feasible due to the low cost of Zn and Cu and the fast kinetics found for NFX degradation.

... From energy-resolved mass spectrometry, the nature and energy distributions of positive and n... more ... From energy-resolved mass spectrometry, the nature and energy distributions of positive and negative ions impinging on the surface of a growing TiO 2 film were investigated as a function of the total pressure P T . The thin films were deposited by DC reactive magnetron ...

Surface and Coatings Technology, 2016

Nb1 - xTixNy thin films (with 0 <= x <= 1 and 0.85 <= y <= 1.15) were deposited from ... more Nb1 - xTixNy thin films (with 0 <= x <= 1 and 0.85 <= y <= 1.15) were deposited from Nb and Ti metallic targets using a hybrid process combining high-power impulse magnetron sputtering (HiPIMS) and DC magnetron sputtering (DCMS) techniques. Two series of Nb1-xTixNy films were deposited in which the HiPIMS mode was applied either to the Nb or to the Ti target while the second target (Ti or Nb) was operated in DCMS mode. The HiPIMS generator was operated at a fixed time-average power of 100 W (5 W cm(-2)) with a pulse-width of 50 mu s and a repetition frequency of 1000 Hz whereas the DC power applied to the second target was varied from 0 to 90 W to adjust the relative contents of Ti or Nb in the films. Depositions were performed in an Ar + N-2 atmosphere at a total pressure of 0.5 Pa. The substrate temperature was fixed at 250 degrees C and the sample holder was biased at -50 V. The films were characterized by XRD, SEM, EDS, nanoindentation, optical and electrical measurements. All the ternary films crystallize in the fcc NaCl-type of the structure. The films exhibit a dense columnar structure and their hardness values increase from 26 for TiN to 35 GPa for NbN. The optical properties of the Nb1 - xTixNy films progressively evolve from those of the fcc-NbN to those of the fcc-TiN as the Ti content x increases from 0 to 1. The room temperature resistivity value decreases from about 300 mu Omega cm (for NbN0.99) down to 25 mu Omega cm (for TiN0.98) as x increases from 0 to 1. In contrast to that, Nb1 - xTixNy films deposited under similar deposition conditions using DCMS exhibit open columnar structure, low hardness values (15 to 22 GPa), high electrical resistivity in the range of 200-360 mu Omega cm, and optical properties without clear correlation with the chemical composition of the films. The peculiar physical properties of these films, compared with those obtained by the hybrid process, are mainly attributed to their open columnar morphology. (C) 2015 Elsevier B.V. All rights reserved.

Thin Solid Films, 2019

The present paper reports on an experimental investigation of the structural, electrical and opti... more The present paper reports on an experimental investigation of the structural, electrical and optical properties of Ru rich Ru 1-x Ti x O 2 thin films. Rutile single-phase Ru 1-x Ti x O 2 thin films have been deposited by reactive hybrid High-power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) at a substrate temperature of 250°C. The HiPIMS source was applied to the Ru target while the DCMS source was connected to the Ti target in order to vary the Ti content in the films. The films are well crystallized and compact with randomly orientated nanocrystallites. The optical properties have been investigated by ellipsometric measurements in the optical energy range from 1.3 eV to 3.3 eV, while the electrical resistivity has been measured in the Van der Paw configuration at room temperature. The electrical resistivity increases gradually from 70 μΩcm for pure RuO 2 to about 243 μΩcm for Ru 1-x Ti x O 2 films with x = 0.13. The optical properties are correlated with the Ti doping. The refractive index n changes from a strong dispersion relationship to a moderate one with increasing Ti content. The Ru 1-x Ti x O 2 thin films have been deposited by reactive hybrid

2018 20th International Conference on Transparent Optical Networks (ICTON), 2018

Single photon technology is enabling for quantum communication and processing. Combining single p... more Single photon technology is enabling for quantum communication and processing. Combining single photon sources, routing circuitry and highly efficient detectors in a high yield, low-loss and scalable fashion represent today a major challenge. Nanophotonic devices allow for the realization of on-chip small footprint architectures for generating, manipulating and detecting single photons. Waveguide-integrated superconducting nanowire single photon detectors are today state-of-the art devices capable of detecting single photons propagating in an integrated photonic circuit with high efficiency, speed and low timing uncertainty. Their excellent metrics in the near-infrared allows to directly interface on-chip devices with existing C-Band communication technology systems. To move towards high communication speed, efficient detectors able to sustain Gcps count rate are desirable. Here we present the design process and the experimental characterization of a new generation of fast detectors, consisting of µm-long NbN superconducting nanowires embedded in a SOI two-dimensional photonic crystal cavity. Almost 70% efficiency at telecommunication wavelengths has been achieved with negligible dark counts and sub-ns recovery time, which could enable Gcps count rates.

RSC Advances, 2015

This study reports the photosensitizing effect/mechanism of FeOx under visible light irradiation ... more This study reports the photosensitizing effect/mechanism of FeOx under visible light irradiation and charge transfer to TiO2 on FeOx–TiO2 cosputtered film.

Applied Catalysis B: Environmental, 2016

Co-sputtered TiO 2-Cu polyester (TiO 2-Cu-PES) under actinic light induced bacterial reduction of... more Co-sputtered TiO 2-Cu polyester (TiO 2-Cu-PES) under actinic light induced bacterial reduction of Escherichia coli in the presence of O 2 (air) and under anaerobic conditions. The bacterial inactivation/oxidation proceeds in the absence of O 2 (air) probably due to the highly oxidative TiO 2 vb(h +) species and the toxic Cu present. By the choice of suitable scavengers, the presence of highly oxidative radicals was confirmed in aerobic media. The E. coli inactivation in aerobic media proceeds on TiO 2-Cu-PES within ∼30 min and with a slower kinetics of ∼90 min in anaerobic media. Malondialdehyde generation a product of bacterial inactivation, was observed on the TiO 2-Cu-PES in air and in lesser amounts under anaerobic conditions. Repetitive bacterial inactivation cycles show a Cu-release of ∼2 ppb/cm 2 by the TiO 2-Cu-PES surface as determined by inductively coupled plasma mass spectrometry (IPC-MS). The Cu released is far below the values reported for the Cu released by TiO 2-Cu-PES samples by sputtering Ti and Cu in sequential order from two targets. By X-ray photoelectron spectroscopy (XPS), redox catalysis by the Cu and TiO 2-species was observed under anaerobic conditions providing further evidence for processes leading to bacterial inactivation in anaerobic media. A mechanism for the TiO 2-Cu-PES bacterial inactivation is suggested consistent with the results reported in this study.

Applied Catalysis A: General, 2015

The kinetics of bacterial reduction of Staphylococcus aureus (MRSA) on co-sputtered TiO 2 /Cu-pol... more The kinetics of bacterial reduction of Staphylococcus aureus (MRSA) on co-sputtered TiO 2 /Cu-polyester (TiO 2 /Cu-PES) was found to be little dependent on the applied light dose. But in the case of Escherichia coli, the bacterial reduction kinetics was observed to be strongly dependent on the applied light dose. The reasons for the different effect of the applied light dose on the bacterial reduction are discussed. Mechanistic considerations are suggested to account for this observation. TiO 2 /Cu-PES obtained by direct current magnetron co-sputtering and the bacterial reduction features compared to PES sputtered individually by TiO 2 and Cu. This study presents the first evidence for the stabilizing effect of TiO 2 on the amounts of the Cu released during bacterial inactivation by co-sputtered surfaces compared to sequential sputtering of Ti and/or Cu on PES. The release of Cu-monitored in the ppb range by inductively coupled plasma-mass spectrometry (ICP-MS) is indicative of an oligodynamic effect leading to bacterial reduction. The bacterial reduction of MRSA ATCC 43300 on co-sputtered TiO 2 /Cu led to a 5 log 10 (99.999%) reduction within 120 min in the dark and 60 min under low intensity actinic light. Diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM) and X-ray fluorescence (XRF) describe the TiO 2 /Cu surfaces investigated in this study.

MRS Proceedings, 2005

AlN/TiN multilayered thin films with layer thickness ranging from 1 nm to 50 nm were synthesized ... more AlN/TiN multilayered thin films with layer thickness ranging from 1 nm to 50 nm were synthesized using rf magnetron sputtering at 400°C. Two series of samples were prepared at the substrate bias of Vb = −25 V and −100 V to modify growth texture of individual layers and verify its influence on the formation of coherent structures. XRD and TEM observations showed that in large period films (tc ≥ 30 nm) each constituent grows under its own kinetic, leading to the formation of nano-crysatlline film randomly oriented with no pronounced texture. Decreasing progressively the layer thickness favours the alignment of (0002) basal plane of w-AlN on (111) plane of TiN, and results in development of strong (111) texture, prerequisite for stabilisation of c-AlN and the formation of epitaxial coherent structures. The degree of crystallographic coherence was found to be higher in TiN(111) oriented films than for TiN(002) textured films. The increase of hardness coincides with the structure transit...

Surface and Coatings Technology, 2001

Journal of Applied Physics, 2009

WC/amorphous carbon (a-C) thin films were deposited by dual magnetron sputtering from individual ... more WC/amorphous carbon (a-C) thin films were deposited by dual magnetron sputtering from individual WC and graphite targets. The influence of film composition and microstructure on the optical and electrical properties was investigated. As evidenced by x-ray photoelectron spectroscopy and grazing angle x-ray diffraction measurements, the WC/a-C films are composite materials made of hexagonal W2C and/or cubic β-WC1−X nanocrystallites embedded in

Applied Catalysis B: Environmental, 2016

Insight is provided in this study for the effect of the TiO 2 film densification/compactness on p... more Insight is provided in this study for the effect of the TiO 2 film densification/compactness on polyethylene (PE-TiO 2) by sputtering TiO 2 at two very different energy levels. Uniform, adhesive low energy films were prepared by direct current magnetron sputtering (DCMS) and compared with films sputtered at high energy levels by high power impulse magnetron sputtering (HIPIMS). Nano-particulate TiO 2 films sputtered by HPIMS presented sizes of ∼10.2 nm compared to films sputtered by DCMS with TiO 2 sizes of ∼16.5 nm as determined by X-ray diffraction (XRD). The E. coli inactivation kinetics was three times faster for the samples sputtered by HIPIMS compared to their DCMS counterparts. This is an unexpected finding since the DCMS presenting larger TiO 2 sized nanoparticles released a higher amount of Ti-ions compared to the HIPIMS samples as monitored by inductively coupled plasma mass-spectrometry (ICP-MS). The Ti-ions released do not seem to react through an oligodynamic effect but diffuse through the less compact TiO 2 sputtered by DCMS. The faster bacterial inactivation kinetics observed by the HIPIMS sputtered samples can be understood in terms of the complete of Ti 4+ /Ti 3+ redox conversion during bacterial inactivation detected by X-ray photo-electron spectroscopy (XPS) compared to the smaller Ti 4+ /Ti 3+ effect observed in the DCMS-samples. A higher optical density was detected for the HIPIMS sputtered samples by diffuse reflectance spectroscopy (DRS). Evidence is presented for the shift in surface potential and local pH during bacterial inactivation under aerobic and anaerobic conditions. A reaction mechanism is suggested based on the findings described in this study. The sputtered films present the potential to hinder biofilm formation on flexible thin polymers/textiles widely used in hospitals and health facilities.

Thin Solid Films, 2001

Boron nitride films deposited by ion beam assisted deposition (IBAD) and triode sputtering system... more Boron nitride films deposited by ion beam assisted deposition (IBAD) and triode sputtering system are studied. The presence of the cubic phase was checked by transmission infrared spectroscopy. The adhesion of the films was very poor, the films delaminated just after deposition. In an attempt to improve the adhesion, the deposition conditions (ion energy and flux) were changed after the

Applied Catalysis B: Environmental, 2016

Uniform adhesive TiO 2-ZrO 2 films co-sputtered on polyester (PES) under low intensity sunlight i... more Uniform adhesive TiO 2-ZrO 2 films co-sputtered on polyester (PES) under low intensity sunlight irradiation discolored methylene blue (MB) within 120 min. The discoloration kinetics was seen to be accelerated by a factor four by TiO 2-ZrO 2-Cu containing ∼0.01% Cu, as determined by X-ray fluorescence (XRF). TiO 2-ZrO 2-Cu also increased also accelerated by a factor the discoloration of MB compared to TiO 2 /Cu(PES). MB discoloration was also monitored under visible light in the solar cavity by using a 400 nm cutoff filter. Photocatalyst surfaces were characterized by spectroscopic methods showing the film optical absorption and by X-ray photoelectron spectroscopy (XPS), the surface atomic percentage concentration up to 120 nm (∼600 layers). The band-gaps of TiO 2-ZrO 2 and TiO 2-ZrO 2-Cu were estimated for films co-sputtered for different times. By Fourier transform attenuated infrared spectroscopy (ATR-FTIR), the systematic shift of the predominating s (CH 2) vibration-rotational MB bands was monitored up to complete MB discoloration under low intensity solar simulated light. Evidence is presented for the OH • generation by TiO 2-ZrO 2-Cu participating in the self-cleaning mechanism. The photo-induced interfacial charge transfer (IFCT) on the TiO 2-ZrO 2-Cu is discussed in terms of the electronic band positions of the binary oxides and Cu intra-gap states. This study presents the first evidence for a Cu-promoted composed of two binary oxide semiconductors accelerating the self-cleaning performance.

DOI to the publisher's website. • The final author version and the galley proof are versions of t... more DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement: