Synthesis, structure, physical properties, and electronic structure of KGaSe_2

摘要

The ternary gallium selenide KGaSe_2 has been synthesized by solid-state reactions and good quality crystal has been obtained. KGaSe_2 crystallizes in the monoclinic space group C2/c with cell dimensions of a = 10.878(2) A, b = 10.872(2) A, c = 15.380(3) A, and β = 100.18(3)°. In the structure, adamantane like [Ga_4Se_(10)]~(8-) units are connected by common corners forming two-dimensional [GaSe_2]~- layers which are separated by K~+ cations. KGaSe_2 exhibits congruent-melting behavior at around 965 °C. It is transparent in the range of 0.47—20.0 urn and has a band gap of 2.60(2) eV. From a band structure calculation, KGaSe_2 is a direct-gap semiconductor. The band gap is mainly determined by the [GaSe_2]~- layer.