Introduction to nanotechnology, comparison of bulk and nanomaterials – change in band gap and large surface to volume ratio, classification of nanostructured materials. Synthesis of nanomaterials – classification of fabrication methods – top down and bottom up methods.
Concept of quantum confinement and phonon confinement
Basic concepts – excitons, effective mass, free electron theory and its features, band structure of solids. Bulk to nano transition – density of states, potential well – quantum confinement effect – weak and strong confinement regime. Electron confinement in infinitely deep square well, confinement in two and three dimension. Blue shift of band gap – effective mass approximation. Vibrational properties of solids – phonon confinement effect and presence of surface modes.
Tools for characterization:
Structural – X-ray diffraction, transmission electron microscope,scanning tunneling microscope, atomic force microscope. Optical – UV – visible absorption and photoluminescence techniques, Raman spectroscopy.
Nanoscale materials – properties and applications:
Carbon nanostructures – structure, electrical, vibration and mechanical properties. Applications of carbon nanotubes
Field emission and shielding – computers – fuel cells – chemical sensors – catalysis – mechanical reinforcement. Quantum dots and Magnetic nanomaterials – applications.
Nanoelectronics and nanodevices:
Impact of nanotechnology on conventional electronics. Nanoelectromechanical systems (NEMSs) – fabrication (lithography) and applications. Nanodevices – resonant tunneling diode, quantum cascade lasers, single electron transistors – operating principles and applications.