Electronic and optical properties for Li1-xAgxAlTe2 alloys: potential transparent conductive material

Abstract

Abstract Using the hybrid functionals combining the special quasi-random structure methods, the properties of LiAlTe2, AgAlTe2, and their alloys (Li1-xAgxAlTe2) are studied. Our study confirms that both LiAlTe2 and AgAlTe2 are direct wide-band gap semiconductors. Moreover, LiAlTe2 possesses high transmittance in the visual light region. Lattice constants and volume of Li1-xAgxAlTe2 alloys satisfy Vegard’s law. The band gaps express nonlinear behavior with the component x, and the optical bowing parameter (b Eg ) is 0.13. The carriers’ effective mass for Li1-xAgxAlTe2 alloys is rapidly decreased by the presence of Ag. When Ag component reaches 0.125, the electron (hole) effective mass is 0.225 (0.271) m0 (m0: static electron’s mass), and the band gap is 3.034 eV. Low transition temperature suggests Li1-xAgxAlTe2 alloys are stable under experimental conditions. Meanwhile, the Li1-xAgxAlTe2 alloys express excellent ductility, which is beneficial for future flexible device applications. Wide band gap, smaller electron (hole) effective mass, thermodynamic stability, and high transmittance in the visual light region indicate Li0.875Ag0.125AlTe2 alloy is a promising transparent conductive material.