Effect of Sr doping on the electronic band structure and optical properties of ZnO: A first principle calculation

Incorporating impurities in ZnO provide opportunities to manipulate its electronic and optical properties, which can be exploited for optoelectronic device applications. Among various elements doped in ZnO crystal structure, limited attempts have been accounted for the Sr–doped ZnO system. Further, no theoretical evidence has been reported so far to explore the Sr–doped ZnO frameworks. Here, we report first principle study for the pure and Sr-doped ZnO (Zn1- x Sr x O) structure. We employed the Perdew–Burke–Ernzerhof exchange–correlation function parameters in generalized gradient approximations. In light of these estimations, we calculated the electronic band gap, density of states, and optical parameters, for example, absorption, dielectric functions, reflectivity, refractive index, and energy-loss. The studies suggested that Sr incorporation expanded the optical band gap of ZnO. In addition, the energy-loss significantly increased with Sr content which might be associated with an increase in the degree of disorder in the crystal lattice with Sr incorporation. Also, significant changes were seen in the optical properties of ZnO with Sr content in the low energy region. The theoretical results were likewise compared with the previously reported experimental data.