Semiconductor nanowires (NWs) are attracting wide interest due to their unique physical properties and potential for application in nanodevices. NWs can be obtained by a number of growth methods, and their highly anisotropic growth originates by the presence of a metal particle, the catalyst, that determines the position and the diameter of the nanostructure. The most widely used catalyst is gold. The growth mechanism of catalyst assisted nanowires involves the incorporation of material both impinging on the catalyst particle and diffusing from the free substrate surface to the sidewalls of the wire. The interplay of these two phenomena is critical especially for the growth of alloy semiconductor compound NWs and one dimensional (1-D) heterostructure. Difference in the surface mobility between the constituents could give compositional inhomogeneities in alloy NWs and degradation of the interface sharpness in 1-D heterostructure. The systematic presence of a metal particle at the NWs tip could be exploited in single NW devices. Moreover, one of the most interesting characteristic of the III-V NWs grown by catalyst assisted self assembling is the peculiarity of having an hexagonal lattice structure (wurtzite), while their bulk and epitaxial parent materials have the cubic structure (zinc blend). In our laboratory we have synthesized GaAs NWs by molecular beam epitaxy (MBE) either using a thin gold, manganese, Ga layer as the growth catalyst or without any catalyst. In this talk some of the basics of NWs, their growth and potential applications will be covered.
Nanotechnology research in Pakistan dates back to late 1990's and at the moment it is one of the hottest research topic in the country. A number of research groups in private and government sector holds promise to bring this futuristic but practical technology to Pakistan. Carbon based Nanotechnology research was initiated in PINSTECH in 1998 by accidental observation of carbon clusters in locally developed heavy ion accelerator. The research was accelerated in 2003 with the funding of Ministry of Science and Technology to make Pakistan's first research laboratory dedicated for carbon based nano-science and technology. In this introductory talk I will give a glimpse of indigenous research we are doing in PINSTECH that includes both experimental and computational areas. The aim of this talk is to prove that Pakistan is not so backward in this high-tech area and we would like to invite and promote youngsters to step into this new but developing area.
This talk will be focused on some of the scientific themes and applications in which electron energies reached for device or process operation are above that of the surrounding lattice or environment. Within the scope of the topic I will attempt to describe the vision of the global nanoscience community which is to 'exploit science in the nano-scale to inspire intelligent devices that can shape the future'. Freeman Dyson once said; "Technology is a gift of God. After the gift of life it is perhaps the greatest of God's gifts. It is the mother of civilizations, of arts and of sciences." With this in mind, I will also talk about what we can do to help take our ideas in the exploitation of knowledge to build good technologies for the future. Examples associated with the scale up of plasma technologies for the growth of carbon nanotube systems, use of organic nanocomposites for the production of solar cells and the novel processing routes of materials for display products and next generation transistors will be utilized. Novel Processes such as Ion beam lithography, Focused ion beams, Smart cut and Dual platform systems are versatile tools for nanoengineering and nanoscience applications and can be used to rapidly prototype and modify a diverse range of nano-devices and sensors. I will discuss the use of these systems for nanoengineeing and fabrication using examples from research.
The talk will be based on synthesis and applications of nanostructures in various areas like energy, photonics, and biology. With the tools available to fabricate devices from top down approach, it is utmost desire to develop techniques, which mimic nature, i.e., assemble atoms and molecules in a manner that these can be used for applications. A lot of effort is being carried out to control the growth of matter at nanoscale. The talk will cover fundamentals of self-assembly and then use of nanostructures/nanoparticles in a variety of devices.
Nanotechnology is design, fabrication and application of nanostructures or nanoparticles, and the fundamental understanding of the relationships between physical properties or phenomena and material dimensions. Nanotechnology is a new field or a new scientific domain, dealing with materials or structures in nanometer scales, typically ranging from sub-nanometers to several hundred nanometers. Nanotechnology also promises the possibility of giving non-conventional properties. Yet another very important aspect of nanotechnology is the miniaturization of current and new instruments, sensors and machines that will greatly impact the world we live in. Examples of possible miniaturization are: biosensors that warn us at the early stage of the onset of disease and preferably at the molecular level and target specific drugs that automatically attack the diseased cells on site, nanorobots that can repair internal damage and remove chemical toxins in human bodies, and nanoscaled electronics that constantly monitor our local environment. Synthesis and processing of nanostructures and nanoparticles are the essential aspect of nanotechnology. Studies on new physical properties and applications of nanostructures and nanoparticles are possible only when these materials are made available with desired size, morphology, crystal structure and chemical composition. The research on nanotechnology is evolving and expanding very rapidly. This workshop will focus primarily on synthesis of inorganic materials. The aim is to summarize the fundamentals and established techniques of synthesis and processing of inorganic nanostructures and nanoparticles so as to provide the audience with a systematic and coherent picture about synthesis and processing of nanomaterials. In addition, a small part of the talk will be devoted to characterization, properties and applications of nanomaterials and nanostructures. This presentation would serve as a general introduction to people just entering the field, and also for experts seeking for information in other subfields.
The development of Nanotechnology has enabled the possibilities to fabricate devices and structures at nanoscale (on the order of few nm). The properties of such nanostructures cannot be described by macroscopic physical models like drift-diffusion equations. And that is where the fundamental constants of nature (e.g. charge of an electron, Planck's constant, spin of an electron, etc) come into play. The purpose of this seminar is to describe how these fundamental constants can be connected with the transport phenomenon at nanoscale and how we can come up with a formalism that can describe the transport phenomenon in these nanostructures in terms of the atomistic theory of matter. We will start with a simple one level model to describe transport through individual molecular levels and then extend our discussion to transport through quantum wires using Nonequilibirum Green's Function (NEGF) methodology. Then we will discuss how to include interactions in our formalism which will connect this formalism to Ohm's Law.
Since the fabrication of transistor and IC's, nanotechnology is bringing yet another revolution in science and technology. This revolution bridges over different disciplines such as chemistry, physics and biology. The present talk is divided into two parts: the first one will present an overview of nanotechnology and the second part will include a discussion of the growth of nano crystals/structures using Buffer Layer Assisted technique.
This seminar will introduce the basics of nanotechnology. Alongwith the fundamentals, it will overview current research trends and the underlying problems in nanotechnology. Focus will be on ceramic nano-particles, such as their synthesis routes (including thermal hydrolysis, hydrothermal processes and solid state reaction). Some applications of nano-ceramics will also be mentioned.
Nanotechnology, the ability to work at the atomic and molecular level, atom by atom to create materials and structures with new capabilities, will fundamentally change electronics, computers, medicine, biotechnology, and many other industries. The current research in this area is meant to explore the science of nanostructures and new materials, to develop the enabling technology for producing new classes of electronic and biological devices, and to educate the scientists and engineers who will carry this vision forward. This talk is about the prospects of Nanotechnology and the challenges in this emerging field. It is targeted to undergraduate students in Physics, Chemistry, Electrical and Mechanical Engineering. The complexity of the topic would be minimal and its level would be elementary. It would span discussion on Carbon Nanotubes, Molecular Electronics, Nano-Electromechanical Systems, Ultrathin (1.7-7nm) oxides and nitrided oxides for CMOS applications and Noise Spectroscopy.