EFFECTS OF SULFUR SUBSTITUTIONAL IMPURITIES ON ZnO STRUCTURE USING DENSITY FUNCTIONAL THEORY

Abstract

Zinc oxide ( ZnO ) electrical properties can be modified by addition of impurities or defects such as vacancies or other substances. We use sulfur ( S ) as a substitutional impurity and present a theoretical study on the characteristics of ZnO structures in its crystal form containing S in substitution of O . For theoretical calculations we used Density Functional Theory (DFT) with pseudopotentials and plane waves. ZnO in crystal form with S in substitution of O at heavy percentage was studied by analyzing properties like lattice characteristics, total energy, and gap energy. Lattice parameters a, b, c, and c/a ratio increase with the S -substituent percentage while the crystal stability decreases. Variation of gap energy shows a decreasing trend with increasing amount of substitution. In this paper, we provide a detailed data useful to identify the effects on ZnO in its crystal form when O is replaced by S that will help to predict if the structural changes on the modified ZnO structures may be suitable for applications in opto-electronics.