New 122-materials for optoelectronic applications: An ab-initio comparison analysis

Abstract To complete and/or modify the optoelectronic properties of conventional semiconductors and in order to improve their yield and performance, it is necessary to research other new semiconductors with tailored physical properties to the desired applications. The compounds, with tetragonal ThCr2Si2-type structure, are new promising ternary materials. Heretofore only a little number of them is investigated. So as to search out suitable semiconductors for optoelectronics, we investigated XY2Z2 (X = Ca, Sr, Ba, Y= Zn, Cd, Z = N, P, As, Sb) ternary compounds using first-principle density functional theory calculations. Several properties are considered as basic criteria for selecting new 122-type semiconductors. From a quantitative point of view, the values of the calculated properties of both semiconductors such as the inter-atomic distance dY-Z, the height h, the static real dielectric function e 1 ( 0 ) , the static refractive index n ( 0 ) and the direct band gap E GAP are in the same order. From a qualitative point of view, we also compared the band structure, the density of states and the optical properties of 122-type semiconductors with their III-V analogs. Calculations show that spin orbit coupling does not influence the band gap values in 122-semiconductors, while they are largely affected by the hydrostatic pressure. This finding is an advantage for the 122-semiconductors since through this strain one can control this important property.