In this work, the electronic structure and optical properties are investigated within the framework of the density functional theory (DFT) for different Na-H co-doping scenarios to find out the suitability of H co-doping technique for achieving p-type conductivity in ZnO. Very low formation energies were found for the H co-doped systems compared to others which suggests that they can suppress other n-type impurities and increase the effect of p-type NaZn defects in the lattice. From the electronic structure calculations, we have found that NaZn doped structures with 50% H co-doping produces the best p-type behavior indicating importance of controlling annealing time. Moreover, from the optical calculations, it has been found that NaZn creates impurity states 174 meV above the valence band and electron concentration in these states can be controlled by H co-doping concentration. H co-doping has not produced any substantial lattice strain as compared to other dopants and structures with Na-H co-doping is transparent in the visible light range.

Bio-composites have diverse functional demands for many structural, electrical, electronic, and medical applications. An expansion of the composite functionality is achieved by manipulating the material and design scheme. Smart selection of matrix-reinforcement combinations will lead to applications that have never even been considered. Research holds a huge potential to create a wide variety of usable materials by mixing different fillers and modifying the parameters. Apart from selecting the polymer and the filler, the engineer will have to understand the compatibility of the polymer and the filler, dispersion, and bonding behavior making the design of polymer nanocomposite a rather complex system. In this chapter, we have tried to display different functional materials development pursuit.