Professor Das will discuss briefly an area of research works in his group. This presentation will focus on certain theoretical approaches used by them to study the physical properties of submicron-to-nano structures of semiconductors. The investigations are based on direct and approximate solutions of time- independent Schroedinger equations for carrier states and statistics in semiconductor nanostructures. Few examples with results and possible applications will be mentioned. The presentation will conclude with brief mention of other areas of research in his group on modelling and design of semiconductor electronic and photonic devices.