There are three categories of materials based on their electrical properties: 1. Conductors, 2. Semiconductors and 3. Insulators. The energy separation between the valence band and the conduction band is called Eg (band gap). The ability to fill the conduction band with electrons and the energy of the band gap determine whether a material is…
· Nanoscience is the science of objects with typical sizes of 1-100 nm. If matter is divided into such small objects the mechanical, electric, optical, and magnetic properties can change. · Simply by finely dispersing ordinary bulk materials new properties can be created: inert materials become catalysts, insulators become conductors, or stable materials become combustible. · Most properties…
Multi-layered materials are heterostructures composed of many alternating layers that are generally stacked in a periodic manner. An artificially multi-layered material is shown schematically in figure below. · The combined thickness of two adjacent layers is called the bilayer repeat length or bilayer period. · The principal characteristic of multilayers is a composition modulation, that is, a…
Systems confined in one dimension, or quasi-2D systems, include discs or platelets, ultrathin films on a surface and multi-layered materials; the films themselves could be amorphous, single-crystalline or Nano crystalline. · A solvent that contains a molecular material that when applied to a surface, chemically aligns itself to form the strongest possible bond and appear as…
Systems confined in two dimensions, or quasi-1D systems, include nanowires, nano rods, nanofilaments and nanotubes: again these could either be amorphous, single-crystalline or polycrystalline (with nanometre-sized grains). The term ‘nano-ropes’ is often employed to describe bundles of nanowires or nanotubes. Types of Nanowires: · Metallic – Made from Nickel, Platinum or Gold · Semi-conducting – Comprises of…
A reduction in the spatial dimension or confinement of particles or quasi particles in a particular crystallographic direction within a structure generally leads to changes in physical properties of the system in that direction. Hence one classification of nanostructured materials and systems essentially depends on the number of dimensions which lie within the nanometre range….
Living systems are governed by molecular behaviour at the nanometre scale, where chemistry, physics, biology, and computer simulation all now converge. Implications for Physics: 1. Nanoscale materials mass is extremely small and gravitational forces become negligible. Instead electromagnetic forces are dominant in determining the behaviour of atoms and molecules. 2. Wave-Particle duality of matter: For…
· The study of objects and phenomena at a very small scale, roughly 1-100 nanometres (nm)is called as Nanoscale science or Nanoscience. Ø To understand how small one nm is let us see few comparisons 1. A Red blood cell is approximately 7000nm wide. 2. Water Molecule is almost 0.3nm across. 3. Human hair which is ~…
Metal nanoparticles (NPs) provide optical, magnetic, and electronic properties which are different from the corresponding bulk metal materials, leading to photothermal, therapeutic, and electronic device applications, respectively. Recent research efforts have explored NPs having complex compositions with controllable sizes and morphologies. Special attention has been given to metal NPs for use as optical materials (i.e.,…
Metal nanoparticles (NPs) nowadays represent the key material in vast range of industrial applications ranging from rough industry to fine medical or biochemical utilization. Gold and silver NPs and their applications are currently of great interest. In recent years, rapid developments in nanotechnology have evolved to the point where inclusion of those entities into smart…