Due to carrier confinement, the absorption characteristics in nanostructures is quite different from the absorption in bulk materials and thin films. Enhancement of optical absorption coefficient has been calculated using a mix of quantum and classical models on silicon nano wires. However, the characteristics did not show the experimentally observed resonant peaks. To improve our models , we determined the electronic band structures of unit cells of nano dimensions . These band structures were very different from the band structures of bulk materials and thin films and produced resonant peaks in the optical absorption spectra showing excitonic processes. The absorption is tunable from the visible region to the near UV portion of the solar spectrum. The excitons show large radiative life times which can help to boost efficiency of solar cells.
Prof. Anand Kulkarni obtained his MS in Solid State Physics from Iowa State University, Ames, Iowa,in 1975 and PhD in Electrical Engineering from University of Nebraska-Lincon, Nebraska in 1979. Since 1978 he worked as a professor in the department of Electrical and Computer Engineering at Michigan Technological University in Houghton Michigan. In 2010 he retired after more than 30 years of service and was offered Professor Emeritus status. His research focus is on Thin Films of Electronic and Opto-electronic Materials, and Photovoltaics. He has published and presented more than 100 research papers. He was reviewer of the journals, Thin Solid Films and Journal of Vacuum Science and Technology. He has been a thesis advisor of more than 30 students who obtained MS and PhD degrees under his supervision.