ACS Nano. 2014 Jul 22;8(7):6556-62. doi: 10.1021/nn501683f.
Since the discovery of graphene, growth of two-dimensional (2D) nanomaterials has greatly attracted attention. However, spontaneous growth of atomic two-dimensional (2D) materials is limitedly permitted for several layered-structure crystals, such as graphene, MoS2, and h-BN, and otherwise it is notoriously difficult. Here we report the gas-phase 2D growth of silicon (Si), that is cubic in symmetry, via dendritic growth and an interdendritic filling mechanism and to form Si nanosheets (SiNSs) of 1 to 13 nm in thickness. Thin SiNSs show strong thickness-dependent photoluminescence in visible range including red, green, and blue (RGB) emissions with the associated band gap energies ranging from 1.6 to 3.2 eV; these emission energies were greater than those from Si quantum dots (SiQDs) of the similar sizes. We also demonstrated that electrically driven white, as well as blue, emission in a conventional organic light-emitting diode (OLED) geometry with the SiNS assembly as the active emitting layers. Tunable light emissions in visible range in our observations suggest practical implications for novel 2D Si nanophotonics.
自从石墨烯被发现以来，二维（2D）纳米材料的生长引起了极大的关注。然而，对于几种层状结构晶体，如石墨烯、MoS2 和 h-BN 等，原子二维（2D）材料的自发生长受到限制，否则就非常困难。在这里，我们通过枝晶生长和枝晶间填充机制报告了立方对称的硅（Si）的气相 2D 生长，从而形成厚度为 1 至 13nm 的硅纳米片（SiNSs）。薄的 SiNSs 在可见光范围内表现出强烈的厚度依赖性光致发光，包括红、绿和蓝（RGB）发射，其相关的能带隙能量范围从 1.6 到 3.2eV；这些发射能量大于具有相似尺寸的硅量子点（SiQDs）的发射能量。我们还证明了在具有 SiNS 组件作为有源发射层的传统有机发光二极管（OLED）几何结构中，可以实现电驱动的白色和蓝色发射。我们的观察结果表明，在可见光范围内可调谐的光发射对新型二维硅纳米光子学具有实际意义。
