Alternative renewable energy source is immensely necessary in view of increase in worldwide energy needs. Since Thermo Electric (TE) power generation is renewable and clean energy source, it is quiet useful to meet the energy demands globally. It leads to overall efficiency of energy generation. Materials which exhibit TE effect have the ability to convert waste heat into electricity. But the efficiency of TE power is lower than possible generation because of the interconnecting linkage between electrical conductivity, thermal conductivity and Seebeck coefficient in bulk materials. The challenge behind this bulk TE material can be broken by introducing nanostructures. Nanostructures are able to disconnect the link between physical parameters such as electrical and thermal conductivity at the interfaces. The main goal of the present report is to report how the reduction in thermal conductivity is achieved without affecting electrical conductivity. In nanostructures, thermal conductivity is eased by increasing phonon scattering without much variation in electrical conductivity. Also, increase in electronic density of states provide increases in carrier concentration and thereby enhances the electrical conductivity. Thus in this report an attempt has been made to indicate the ways to enhance the figure of merit in nanostructures.