Structural and optoelectronic properties of CsLnZnTe3 (Ln = La, Pr, Nd and Sm)

Zinc telluride is a versatile wide band gap semiconductor used in many applications. But it has certain limitations like large dimensions and large band gaps. Introducing alkali metal to its bulk lattice (3D) can reduce its dimensions and lanthanide can produce a red shift in the energy gap by converting it into quaternary compounds. The alkali and lanthanide incorporated quaternary zinc tellurides CsLnZnTe3 (Ln = La, Pr, Nd and Sm) form layered crystal structure in which 2 infinity[LnZnTe3]- layers are separated by Cs+ layer. The famous lanthanide contraction is experimental both from lattice constants and bond lengths. The calculated band gaps are 2.26, 2.28, 2.12, 2.05 eV for CsLaZnTe3, CsPrZnTe3, CsNdZnTe3 and CsSmZnTe3, respectively. These compounds show direct band gap nature. The energy band gaps of these compounds have not been evaluated yet both experimentally and theoretically. Energy loss functions, refractive index and dielectric functions were also calculated to explore the potential applications of CsLnZnTe3 in optoelectronic devices.(c) 2022 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.