Dr. Aniruddha Chakraborty

Few Interesting Questions :                                                        <<back

 1. The suppression of a systems melting point is one of the known property of nano-scale materials (semiconductor & metal). Can you think of an1. The suppression of a systems melting point is one of the known property of nano-scale materials (semiconductor & metal). Can you think of any potential applications that exploit this property ?

 2. Provide examples of some companies that are currently producing nano-related products.

 3. Before 1998, there were very few Universities/Institutes dedicated to Nano-science. Today, there are a number of Institutions/Universities dedicated to Nano-science. Can you find a few of these Universities/Institutions ?

 4. Assume Drexler is right and one "assembler" can assemble a million of atoms within a second. Roughly how long would it take for one of these assemblers to put together a cricket ball ? Make assumptions where necessary and state your assumptions explicitly.

 5. Measuring distances on the nanometer scale is an important task for a number of scientific investigations. Find at least one examples.

 6. More recently, colloidal nanoparticles have been used as molecular rulers, do you have any idea of how the technology works ?

 7. Having seen many applications of low dimensional materials, attempt to devise an original application of wells, wires or dots (or any other nano-system). Describe your application, state why it has advantages over bulk analogues, and explain how you intend to make such a device.

 8. Read about Magnetotactic Bacteria that naturally contain magnetic particles. Find out how these bacteria synthesize nanoparticles. Then ask yourself why they would want them in the first place.

 9. Provide examples of some companies that are currently producing nano-related products.

 10. Does the effective band gap of a low dimensional semiconductor increase with degree of confinement (the band gap is akin to the HOMO-LUMO gap of a molecular system) ?

 11. What is dark exciton ?

 12. Consider the well-known progression of colours possessed by ensembles of different-sized colloidal CDSe quantum dots. The samller particle appear yellow. Larger one appear red. Think about why small diameter ensembles appear yellow while larger-diameter ensembles appear red. Similarly, it is well known that gold nanoparticles generally have a distinct ruby red colour. By contrast, aggregated gold ensembles appear blue to the eye. Think about the origin of these colours as well.

 13. There is considerable interest in the community in going beyond the generic classes of nanosctructures. For example there is interest in combining individual quantum dots to make so called quantum dot "molecules". Alternatively, one can make more extended structures, leading to artificial "solids" sometimes called superlattices. Find examples of each in the literature.

 14. Find two examples in the current literature, where materials are said to be in any one of the various confinement regimes, described in the class.

 15. Explain what the size of the exciton Bohr radius mean for achieving quantum confinement. What systems are easier for achieving this effect ?

 16. Find an example from the literature where the surface to volume ratio is invoked to explain some special property of nanostructure.

 17. What are the some of the broader moral and ethical implications of nanoscience and nanotechnology ?

 18. One of the major concerns these days with nanoscience and nanotechnology has to do with health risks. There are those who think that all nano-related research should be stopped until its health risks have been fully evaluated. Can you think about the possible 'origin' of these health risks ?