Crystal and electronic structure of a quasi-two-dimensional semiconductor Mg₃Si₂Te₆

We report the synthesis and characterization of a Si-based ternary semiconductor Mg$_3$Si$_2$Te$_6$, which exhibits quasi-two-dimensional structure, where trigonal Mg$_2$Si$_2$Te$_6$ layers are separated by Mg ions. Ultraviolet-visible absorption spectroscopy density functional theory calculations were performed to investigate electronic structure. The experimentally determined direct band gap is 1.39 eV, consistent with value function calculations. Our results reveal that Mg$_3$Si$_2$Te$_6$ relatively narrow gap, potential candidate for infrared optoelectronic devices.