Vast Structural and Polymorphic Varieties of Semiconductors AMM′Q4 (A = K, Rb, Cs, Tl; M = Ga, In; M′ = Ge, Sn; Q = S, Se)

Nine
new chalcogenide semiconductors AInM′Q4 (A+ = K+, Rb+, Cs+, Tl+;
M′4+ = Ge4+, Sn4+; Q2– = S2–, Se2–) have been prepared
by solid-state syntheses and structurally characterized by single-crystal
X-ray diffraction techniques. These new phases fill in the missing
links in these quaternary systems and crystallize in various two-dimensional
layered polymorphs, while combinations containing large M3+ and M′4+ cations also adopt an extended three-dimensional
(3D) network structure. The AMM′Q4 materials exhibit
a wide range of band gaps with colored selenides (1.8 eV < Eg < 2.3 eV) and mostly white sulfides (2.5
eV < Eg < 3.6 eV). These phases
have direct band gaps except for the thallium analogues and the cubic
AGaSnSe4-cP84. First-principles theoretical
calculations of the electronic band structures reveal critical insight
into the structure/property relationships of these materials. The
distinct polymorphism of these quaternary phases is studied by discussing
kinetic and thermodynamic factors responsible for the crystallization,
structural considerations, and complementary density functional theory
(DFT) calculations.

九种新型硫族化合物半导体 AInM′Q4（其中 A+ 为 K+、Rb+、Cs+ 或 Tl+；M′4+ 为 Ge4+ 或 Sn4+；Q2– 为 S2– 或 Se2–）已通过固态合成方法制备成功，并采用单晶X射线衍射技术对其结构进行了表征。这些新型相填补了相应四元体系中缺失的环节，并以多种二维层状多晶形态结晶。含有较大M3+ 和 M′4+ 阳离子的组合也采取了扩展的三维（3D）网络结构。AMM′Q4 材料展现出宽泛的能带间隙，其中彩色硒化物（1.8 eV < Eg < 2.3 eV）和大多数白色硫化物（2.5 eV < Eg < 3.6 eV）具有显著的颜色。除了铊类似物和立方晶系的 AGaSnSe4-cP84 外，这些相均具有直接能带隙。基于第一性原理的理论计算揭示了这些材料的结构-性能关系。通过对结晶动力学和热力学因素、结构考虑以及补充的密度泛函理论（DFT）计算的分析，研究了这些四元相独特的多晶形态。