Computational simulation-based study of novel ZnO Buckyball structures

A novel Zinc Oxide Buckyball (ZnO-b) system has been optimized using the first principle density functional theory (DFT). The study of the structural, electronic, and optical properties of both the pristine and Al, Ga, and Ag-doped ZnO-b and ZnO-h (ZnO hexagonal) systems have been reported here. A comparative study of the variations which occurred due to changes in the crystal structure, dopant element as well as doping site was done for both systems. The study includes the structural analysis followed by the electronic analysis with the study of Density of States (DOS), Partial Density of States (PDOS), and at last the Optical analysis of the systems. The bandgap engineering due to structural variations in ZnO is observed here as metal-doped ZnO-h structures showed a vast shift towards a smaller bandgap value, showing enhancement in the metallic behaviour, while for ZnO-b it varied between 1.52 eV-2.94 eV with similar doping. It was observed that mostly the value of the cell volume and the bandgap decreases with an increase in the atomic radii of the dopant atoms due to quantum confinement effects. Ag-doped sample has shown a better optical conductivity with lower absorbance as compared to other dopants in the ZnO-b structure, which makes it a suitable material for optoelectronic applications. Overall, in the buckyball structures properties of dopants are predominating whereas, in hexagonal structures, properties of ZnO are predominating. This makes the ZnO-b structure a useful material for biomedical applications along with optoelectronic devices. This work also opens a wide area of study for applications of these novel structures from biomedicines to optoelectronic devices by precisely controlling their physical properties.