One-dimensional nanostructures, such as nano-wires and nano-belts, offer a high degree of interest for
furthering the current state of nanotechnology research and development. Higher aspect ratio, diameter
dependent band-gap, and increased surface scattering for electrons are some of the more significant features
in which nano-wires differ from their normal counterparts, which exhibit bulk properties. Many methods for
the fabrication of nano-wires, nano-rods and nano-tubes have been developed including lithographic and non-lithographic
techniques. Among them Template synthesis (non-lithographic technique) is a versatile, flexible
and simple approach to the fabrication of metallic nano-wires and nano-tubes. We have successfully
fabricated arrays of Cu-Se 5μm, 1μm, 100nm, 40nm hetero structures using a non-lithographic technique of
filling cylindrical pores of track-etch membranes with Cu and Se materials. These were then analyzed by
scanning electron microscope. I-V curves of deposited Cu-Se hetero structures of varying diameters were also
recorded which show increase of negative differential resistance with decrease in diameters of these hetero-structures. The effect of thermal annealing at different temperatures causing thermal stress on these
synthesized structures was also studied.
Electrodeposition is a versatile technique combining low processing cost with ambient conditions that can be used to
prepare metallic, polymeric and semiconducting nano/micro structures. In the present work, track-etch membranes
(TEMs) of makrofol (KG) have been used as templates for synthesis of ZnS nanowalled microtubules using
electrodeposition technique. The morphology of the microtubules was characterized by scanning electron microscopy.
Size effects on the band gap of tubules have also been studied by UV-visible spectrophotometer.
The tunneling phenomenon assumes significant role in devices, which are put to use in information processing, data storage and transmission, digital functioning etc. The requirements call for low dimensions, low weight, low power consumption, high frequency etc. Template synthesis is an elegant approach for synthesizing nano/micro sized resonant tunneling diodes (RTDs). Using track-etch membranes as templates, we report here on the nano/micro fabrication of RTDs using binary systems like Cu-Se, Zn-Se etc and present their I-V characteristics, besides the effect of temperature and size variation of the structures.
The miniaturization of devices and synthesis of new materials have a tremendous role in the development of powerful
electronics as well as material based technologies in other areas but for the laws of quantum mechanics posing
limitations besides the increasing cost and difficulties in manufacturing at such a small scale. The quest, therefore, for
the alternative technologies have stimulated a surge of interest in nano-meter scale materials and devices in the recent
years. Metallic nano wires are the most attractive materials because of their unique properties having myriad
applications like interconnects for nano-electronics, magnetic devices, chemical and biosensors, where as the hollow
tubules are equally considered to be candidate for more potent applications- both in physical as well as biosciences.
Materials' processing for nano-structured devices is indispensable to their rational design. The technique, known as
"Template Synthesis", using electrochemical/electro less deposition is one of the most important processes for
manufacturing nano/micro structures, nano-composites and devices and is relatively inexpensive and simple. The
technique involves in using membranes- ion crafted ones (popularly known as Particle Track-Etch Membranes or
Nuclear Track Filters), alumite substrate membranes, besides other types of membranes as templates. The parameters
viz., diameter as well as length i.e., the aspect ratio, shape and wall surface traits in these membranes are controllable. In
the present work, a detailed review of this technique, synthesis of nano/micro materials including hybrid materials and
devices like field-ion emitters, resonant tunneling diodes (RTDs) etc. will be presented including most of the results
obtained in our laboratory.