Center for Advancing Materials Performance from the Nanoscale, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
Nanoscale. 2018 Apr 26;10(16):7363-7368. doi: 10.1039/c8nr01747f.
The recently discovered two-dimensional (2D) group IV chalcogenides attract much attention owing to their novel electronic and photonic properties. All the reported materials of this class favor (distorted) octahedral coordination via p bonding; by contrast, in the dichalcogenides where the bonding tendency approaches sp3, no corresponding 2D phase has been realized so far. Here, by engineering the composition of a chalcogenide heterostructure, the hitherto elusive GeTe2 is experimentally observed in a confined 2D environment. Density functional theory simulations predict the existence of a freestanding monolayer of octahedrally coordinated GeTe2 under tensile strain, and the existence of GeSe2 and GeS2 in the same form under equilibrium conditions. These 2D germanium dichalcogenides are either metallic or narrow gap semiconducting, and may lead to new applications in nanoscale electronics.
最近发现的二维（2D）IV 族硫属化物因其新颖的电子和光子特性而备受关注。该类所有已报道的材料都通过 p 键有利于（扭曲）八面体配位；相比之下，在键合趋势接近 sp3 的二硫属化物中，迄今尚未实现相应的 2D 相。在这里，通过设计硫属化物异质结构的组成，实验上在受限的 2D 环境中观察到了迄今难以捉摸的 GeTe2。密度泛函理论模拟预测在拉伸应变下存在八面体配位的独立单层 GeTe2，在平衡条件下存在 GeSe2 和 GeS2 以相同的形式存在。这些二维锗二硫属化物要么是金属的，要么是窄带隙半导体的，可能会在纳米电子学领域带来新的应用。
