Nanostructured materials nanoscale manipulation

Nanoscience and technology is a field that focuses on 1) the development of synthetic methods and surface analytical tools for building structures and materials, typically on the sub-100 nanometer scale, 2) the identification of the chemical and physical consequences of miniaturization, and 3) the use of such properties in the development of novel and functional materials and devices. Thus, this field is of greatest interest to handle nanoparticles, nanostructured materials, nanoporous materials, nanopigments, nanotubes, nanoimprinting, quantum dots, and so on and has already led to many innovative applications, particularly in materials science [18, 19]. For basic investigations, an important role is played by manipulation or imaging nanoscale techniques (e.g., AFM and STM). 

Nanotechnology is the branch of engineering that deals with the manipulation of individual atoms, molecules, and systems smaller than 100 nanometers. Two different methods are envisioned for nanotechnology to buUd nanostructured systems, components, and materials. One method is the top-down approach and the other method is called the bottom-up approach. In the top-down approach the idea is to miniaturize the macroscopic structures, components, and systems toward a nanoscale of the same. In the bottom-up approach the atoms and molecules constituting the building blocks are the starting point to build the desired nanostmcture [96-98]. 

The basic difference between conventional processing and nanofabrication is the dimension of the structures to be fabricated. There are basically two possible approaches top-down and bottom-up approaches. In the top-down approach, micro and nanostructures are achieved by controlled removal of extra amount of material by applying an external source of energy such as mechanical, thermal, chemical, and electrochemical energy. The top-down approach of micro and nanofabrication is schematically shown in Fig. 1.2. This approach is difficult to apply at nanoscale however at microscale, it has been utilized successfully by various means. In the bottom-up approach, positions of atoms or molecules are manipulated to build up the nanodevices or nanostmctures, as illustrated in Fig. 1.3. Various techniques of this approach are under development at the laboratory level and need further improvements. 

Bottom-Up Nanofabrication. Bottom-up nanofabrication is one approach to nanomanulacturing. This process builds a specific nanostructure or material by combining components of atomic and molecular scale. Creating a structure this way is time-consuming, so scientists are working to create nanoscale materials that will spontaneously join to assemble a desired structure without physical manipulation. 

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