Theoretical investigations on transition metal trioxide (TMO3) cluster incorporated monolayer aluminum nitride (AlN) using DFT technique

Abstract

Adopting first-principles density function theory (DFT) calculations, the effects of TMO3 (TM = Ti, Cr, Mn, Fe, Co and Zn) cluster substitution on the physical parameters of monolayer AlN are investigated. Through charge difference diagrams it is seen that, TMO3 clusters lend their charge carriers to the AlN, hence introducing n-type doping process. Unfilled TM atom d electrons O atom p electrons introduce magnetic behaviors, since some of the TMO3-AlN systems carry finite magnetic moments. Spin densities of TMO3-AlN systems suggest the, spin density disproportion is restricted in the vicinity of impurity clusters; the charge carriers induced by impurity clusters carry clockwise spin direction. Monolayer AlN is a semiconducting material, but TMO3 substitution changes the valence and conduction electron energies of AlN sheet, thereby making it semimetal/half metal by nature. Calculated formation energies (EF) for all TMO3-AlN systems fit within specified range, suggesting that TMO3 cluster substitution in AlN layer is thermodynamically possible and stable TMO3-AlN hybrid systems can be synthesized. We also calculate the optical parameters of TMO3-AlN hybrid systems and compare it with pure AlN sheet parameters. It is seen that, TMO3 clusters greatly improve the absorption coefficient of AlN sheet in 0–2.5 eV energy range, while pure AlN layer depicts zero absorption in this energy range. Static reflectivity of AlN is increased after TMO3 cluster substitution. Refractive index 'n' obtains larger static value after TMO3 incorporation in AlN sheet. The extinction coefficient 'k' gains its peak intensities in the visible energy spectrum, which in turn introduces a red-shift in the absorption coefficient of monolayer AlN, as extinction and absorption coefficients are closely related to each other. Results generated during this work suggest that, TMO3 cluster incorporation in AlN sheet can produce unique complex material that can be useful for emerging functionalities in nanotechnology.