S. K. Chakarvarti

Large-scale synthesis of uniform nickel nanowires and their characterisation

Nickel nanowires were synthesised using template synthesis technique. Commercial polycarbonate membranes having pore diameter 100 nm were used as templates. Scanning electron microscopy depicted that the diameter and length of nanowires are same as that of pore diameter and thickness of the template membrane. X-ray diffraction and energy dispersive X-ray fluorescence recommended that the nanowires are of pure nickel metal rather than a nickel compound. Room temperature magnetic characterisation was performed using a vibrating sample magnetometer. The value of saturation magnetisation was observed as different for nickel nanowires with different aspect ratio.

MEASUREMENT OF AVERAGE ETCHED PORE RADIUS IN ION TRACK MEMBRANES THROUGH CONDUCTOMETRIC TECHNIQUE

In the present work, average pore radius in etched PC and PET membranes, exposed to various heavy ions, has been determined using the conductometric technique. The average pore radius, measured directly through optical microscope, has been found to be higher (15%) than the values determined using the conductometric method.

Template-Based Synthesis of Nano/Micro Structures on a Semiconducting Substrate

In recent years, nano/micro wires have attracted considerable attention because of their extraordinary physical properties and enormous potential for applications in numerous fields of research and technology. Among the methods widely used to create nanowires, electrochemical deposition in the pores of ion-track polymer membranes have turned out to be very suitable. This method may also be used to synthesize nano/micro structures on the substrate itself to prevent post-synthesis manipulations. For this, the polycarbonate layer is spin coated on the semiconducting substrate and then irradiated with heavy ions. Chemical etching of these latent tracks leads to the formation of nano-/micro-size pores. After depositing metal in these pores, the polycarbonate templates are removed by dissolving them in dichloromethane, leading to the formation of nanowires standing on the substrate itself. Using this technique, we have studied VI characteristics of metallic nano/micro wires grown on the silicon substrate. These nano/micro structures show Schottky behavior when forward biased and ohmic behavior when reversed biased.

ELECTROLYTIC TRANSPORT THROUGH CYLINDRICAL ETCHED PORES IN POLYETHYLENE TEREPTHALATE TRACK-ETCHED MEMBRANE

In the present work, electrolytic transport phenomena is studied for different electrolytes (LiCl, NaCl, KCl of different concentrations) at room temperature (25 ± 2°C) through etched pores with different diameters having cylindrical shape in track-etched membranes of polyethylene terepthalate (PET) with pore density of the order of 106/cm2. Electric potential has been used as the driving force. It has been observed that electrolytic transport through pores is different for different electrolytes, depending strongly on size of cations and is independent of size of anions. In the case of cylindrical pores, there has not been found appreciable change in forward and backward resistances.

POLYPYRROLE NANOWIRES GENERATION USING CHEMICAL SYNTHESIS THROUGH ION TRACK MEMBRANES

Polypyrrole nanocylinders were produced by non-galvanically (chemically) synthesizing polypyrrole within the pores of nanoporous polycarbonate ion track-etched membranes. The morphology of the nanowires was characterized by scanning electron microscopy. The electrical conductivity of the nanocylinders was calculated by leaving the nanocylinders fixed in the insulating template membrane and evaluating the transmembrane resistance.

Nano-/micro metallic wire synthesis on Si substrate and their characterization

Nano-/micro wires of copper are grown on semiconducting Si substrate using the template method. It involves the irradiation of 8 um thick polymeric layer coated on Si with150 MeV Ni ion beam at a fluence of 2E8. Later, by using the simple technique of electrodeposition, copper nano-/micro wires were grown via template synthesis. Synthesized wires were morphologically characterized using SEM and electrical characterization was carried out by finding I-V plot.

Field emission and I–V characteristics of template synthesised nickel nanowires on semiconducting substrate

Ion track technology makes it possible to produce a low cost template for the synthesis of nanowires. In this article, spin-coated polycarbonate films have been irradiated by energetic 150 MeV Ni ion at a fluence of 8E7, followed by UV irradiation and chemical etching in aqueous NaOH (6N, 29°C). Ni nanowires were electrochemically synthesised in the pores created in the polycarbonate film. The nanostructures thus synthesised were morphologically analysed using scanning electron microscopy and further studied for their electrical and field emission properties.

LARGE SCALE SYNTHESIS OF Ag2S NANOWIRES AND THEIR ELECTRICAL CHARACTERIZATION

In this paper, large scale synthesis of Ag2S nanowires having diameter 100 nm using chemical reaction is reported. Nanochannels in anodic alumina membrane were utilized as templates. Scanning electron microscopy was used for morphological study of nanowires. X-ray diffraction depicted the monoclinic nature of Ag2S nanowires. Energy dispersive X-ray fluorescence recommended that the nanowires are of pure silver sulfide rather than any silver compound. Nonlinear I–V characteristics were observed for Ag/Ag2S/Ag heterostructures.

Template Synthesis Of Copper Nanowires Via Electrodeposition Technique And Their Characterization

Copper nanowires have been synthesized successfully using template assisted electrodeposition technique. Commercial polycarbonate membrane (Whatman, Japan) having pore diameter 100 nm, thickness 10 μm and pore density 107 pores/cm2 was used as template. Scanning electron microscopy and X‐ray diffraction techniques were used to characterize the synthesized copper nanowires. XRD and SEM results reveal that polycrystalline copper nanowires were obtained with fcc lattice structure having diameter equal to the diameter of the template used.

A Model for Cu-Se Resonant Tunneling Diodes Fabricated by Negative Template Assisted Electrodeposition Technique

In this paper, the authors present and discuss a model for Cu-Se nano resonant tunneling diodes (RTDs) fabricated by negative template assisted electrodeposition technique and formulate the mathematical equations for it. The model successfully explains the experimental findings.