Vlad Andrei Antohe - Academia.edu (original) (raw)

Papers by Vlad Andrei Antohe

Research paper thumbnail of The Effect of Ionizing Radiations on the Structural, Electrical and Optical Properties of AIIBVI Polycrystalline Thin Films Used as Solar Cell Materials

MRS Proceedings, 2007

ABSTRACT The effects of irradiation with high-energy protons (3 MeV, up to a fluency of 1013 prot... more ABSTRACT The effects of irradiation with high-energy protons (3 MeV, up to a fluency of 1013 protons/cm2), on structural, electrical and optical properties of polycrystalline CdS and CdTe thin films have been investigated. XRD investigation has revealed that the films ...

Research paper thumbnail of Self-seeded electrochemical growth of ZnO nanorods using textured glass/Al-doped ZnO substrates

Applied Surface Science, 2014

ABSTRACT In this work, large and dense arrays of zinc oxide (ZnO) nanorods (NRs) were fabricated ... more ABSTRACT In this work, large and dense arrays of zinc oxide (ZnO) nanorods (NRs) were fabricated by an improved template-free electrodeposition (ECD) route on top of home-made Al-doped ZnO (AZO) thin films deposited on glass. The AZO layer, acting as transparent conducting oxide, was found to display enhanced electrical and morphological properties compared to other commercially available substrates, facilitating the subsequent electrochemical growth of the ZnO nanostructures. In addition, its intrinsic columnar nature strengthened the vertical orientation of the obtained ZnO NRs. The one-step low-temperature electrochemical method did not require any additional seeding layer, being suitable for applications in which the process simplicity and substrate's thermal toughness are essential requirements. The ECD protocol was optimized as a function of the process temperature and duration, demonstrating the possibility to yield reasonable aspect-ratio ZnO NRs in a relatively short time synthesis. Further structural studies confirmed the excellent orientation along c-axis of the ZnO Wurtzite phase and have shown a polycrystalline nature of the NRs, with a well-defined hexagonal symmetry of the crystallites.

Research paper thumbnail of Nanowire-Decorated Microscale Metallic Electrodes

Research paper thumbnail of Template-free electrodeposition of highly oriented and aspect-ratio controlled ZnO hexagonal columnar arrays

Nanotechnology, 2012

We report an easy one-step template-free electrodeposition method for preparing large arrays of Z... more We report an easy one-step template-free electrodeposition method for preparing large arrays of ZnO hexagonal nanocolumns, vertically oriented on a Au-coated Si substrate. Systematic scanning electron microscopy investigations revealed the potential of this method for obtaining a high degree of verticality and orientation of the nanostructures and for controlling their aspect-ratio in an easy manner. Further structural studies demonstrated that the as-obtained ZnO nanocolumns present a well defined hexagonal symmetry exhibiting an excellent crystallinity.

Research paper thumbnail of Template-Grown NiFe/Cu/NiFe Nanowires for Spin Transfer Devices

Nano Letters, 2007

We have developed a new reliable method combining template synthesis and nanolithography-based co... more We have developed a new reliable method combining template synthesis and nanolithography-based contacting technique to elaborate current perpendicular-to-plane giant magnetoresistance spin valve nanowires, which are very promising for the exploration of electrical spin transfer phenomena. The method allows the electrical connection of one single nanowire in a large assembly of wires embedded in anodic porous alumina supported on Si substrate with diameters and periodicities to be controllable to a large extent. Both magnetic excitations and switching phenomena driven by a spin-polarized current were clearly demonstrated in our electrodeposited NiFe/Cu/ NiFe trilayer nanowires. This novel approach promises to be of strong interest for subsequent fabrication of phase-locked arrays of spin transfer nano-oscillators with increased output power for microwave applications.

Research paper thumbnail of Nanowires and nanostructures fabrication using template methods: a step forward to real devices combining electrochemical synthesis with lithographic techniques

Journal of Materials Science: Materials in Electronics, 2009

One of the great challenges of today is to find reliable techniques for the fabrication of nanoma... more One of the great challenges of today is to find reliable techniques for the fabrication of nanomaterials and nanostructures. Methods based on template synthesis and on self organization are the most promising due to their easiness and low cost. This paper focuses on the electrochemical synthesis of nanowires and nanostructures using nanoporous host materials such as supported anodic aluminum considering it as a key template for nanowires based devices. New ways are opened for applications by combining such template synthesis methods with nanolithographic techniques.

Research paper thumbnail of Nanowire-templated microelectrodes for high-sensitivity pH detection

Applied Physics Letters, 2009

A highly sensitive pH capacitive sensor has been designed by confined growth of vertically aligne... more A highly sensitive pH capacitive sensor has been designed by confined growth of vertically aligned nanowire arrays on interdigited microelectrodes. The active surface of the device has been functionalized with an electrochemical pH transducer ͑polyaniline͒. We easily tune the device features by combining lithographic techniques with electrochemical synthesis. The reported electrical LC resonance measurements show considerable sensitivity enhancement compared to conventional capacitive pH sensors realized with microfabricated interdigited electrodes. The sensitivity can be easily improved by changing only the thickness of the functional layer.

Research paper thumbnail of The Effect of Ionizing Radiations on the Structural, Electrical and Optical Properties of AIIBVI Polycrystalline Thin Films Used as Solar Cell Materials

MRS Proceedings, 2007

ABSTRACT The effects of irradiation with high-energy protons (3 MeV, up to a fluency of 1013 prot... more ABSTRACT The effects of irradiation with high-energy protons (3 MeV, up to a fluency of 1013 protons/cm2), on structural, electrical and optical properties of polycrystalline CdS and CdTe thin films have been investigated. XRD investigation has revealed that the films ...

Research paper thumbnail of Self-seeded electrochemical growth of ZnO nanorods using textured glass/Al-doped ZnO substrates

Applied Surface Science, 2014

ABSTRACT In this work, large and dense arrays of zinc oxide (ZnO) nanorods (NRs) were fabricated ... more ABSTRACT In this work, large and dense arrays of zinc oxide (ZnO) nanorods (NRs) were fabricated by an improved template-free electrodeposition (ECD) route on top of home-made Al-doped ZnO (AZO) thin films deposited on glass. The AZO layer, acting as transparent conducting oxide, was found to display enhanced electrical and morphological properties compared to other commercially available substrates, facilitating the subsequent electrochemical growth of the ZnO nanostructures. In addition, its intrinsic columnar nature strengthened the vertical orientation of the obtained ZnO NRs. The one-step low-temperature electrochemical method did not require any additional seeding layer, being suitable for applications in which the process simplicity and substrate's thermal toughness are essential requirements. The ECD protocol was optimized as a function of the process temperature and duration, demonstrating the possibility to yield reasonable aspect-ratio ZnO NRs in a relatively short time synthesis. Further structural studies confirmed the excellent orientation along c-axis of the ZnO Wurtzite phase and have shown a polycrystalline nature of the NRs, with a well-defined hexagonal symmetry of the crystallites.

Research paper thumbnail of Nanowire-Decorated Microscale Metallic Electrodes

Research paper thumbnail of Template-free electrodeposition of highly oriented and aspect-ratio controlled ZnO hexagonal columnar arrays

Nanotechnology, 2012

We report an easy one-step template-free electrodeposition method for preparing large arrays of Z... more We report an easy one-step template-free electrodeposition method for preparing large arrays of ZnO hexagonal nanocolumns, vertically oriented on a Au-coated Si substrate. Systematic scanning electron microscopy investigations revealed the potential of this method for obtaining a high degree of verticality and orientation of the nanostructures and for controlling their aspect-ratio in an easy manner. Further structural studies demonstrated that the as-obtained ZnO nanocolumns present a well defined hexagonal symmetry exhibiting an excellent crystallinity.

Research paper thumbnail of Template-Grown NiFe/Cu/NiFe Nanowires for Spin Transfer Devices

Nano Letters, 2007

We have developed a new reliable method combining template synthesis and nanolithography-based co... more We have developed a new reliable method combining template synthesis and nanolithography-based contacting technique to elaborate current perpendicular-to-plane giant magnetoresistance spin valve nanowires, which are very promising for the exploration of electrical spin transfer phenomena. The method allows the electrical connection of one single nanowire in a large assembly of wires embedded in anodic porous alumina supported on Si substrate with diameters and periodicities to be controllable to a large extent. Both magnetic excitations and switching phenomena driven by a spin-polarized current were clearly demonstrated in our electrodeposited NiFe/Cu/ NiFe trilayer nanowires. This novel approach promises to be of strong interest for subsequent fabrication of phase-locked arrays of spin transfer nano-oscillators with increased output power for microwave applications.

Research paper thumbnail of Nanowires and nanostructures fabrication using template methods: a step forward to real devices combining electrochemical synthesis with lithographic techniques

Journal of Materials Science: Materials in Electronics, 2009

One of the great challenges of today is to find reliable techniques for the fabrication of nanoma... more One of the great challenges of today is to find reliable techniques for the fabrication of nanomaterials and nanostructures. Methods based on template synthesis and on self organization are the most promising due to their easiness and low cost. This paper focuses on the electrochemical synthesis of nanowires and nanostructures using nanoporous host materials such as supported anodic aluminum considering it as a key template for nanowires based devices. New ways are opened for applications by combining such template synthesis methods with nanolithographic techniques.

Research paper thumbnail of Nanowire-templated microelectrodes for high-sensitivity pH detection

Applied Physics Letters, 2009

A highly sensitive pH capacitive sensor has been designed by confined growth of vertically aligne... more A highly sensitive pH capacitive sensor has been designed by confined growth of vertically aligned nanowire arrays on interdigited microelectrodes. The active surface of the device has been functionalized with an electrochemical pH transducer ͑polyaniline͒. We easily tune the device features by combining lithographic techniques with electrochemical synthesis. The reported electrical LC resonance measurements show considerable sensitivity enhancement compared to conventional capacitive pH sensors realized with microfabricated interdigited electrodes. The sensitivity can be easily improved by changing only the thickness of the functional layer.