论文标题
范德华材料上无处不在的烃污染的组成和结构
The composition and structure of the ubiquitous hydrocarbon contamination on van der Waals materials
论文作者
论文摘要
单层范德华（VDW）材料的行为受到表面直接原子环境的深刻影响，一个很好的例子是人工异质结构中无数的新兴特性。同样重要的是吸附物从环境中沉积在其表面上。尽管VDW界面众所周知，但我们对大气污染的了解受到严重限制。在这里，我们表明：石墨烯，石墨，HBN和MOS2表面上的常见环境污染由自组织的分子层组成，该分子层在环境暴露的几天内形成。使用低温STM测量值，我们对该adlayer的原子结构进行成像，并与红外光谱结合使用，将污染物分子识别为正常烷烃，长度为20-26个碳原子。通过其自我组织的能力，烷烃层置换了歧管其他机载污染物物种，封闭了VDW材料的表面，并可能主导其与环境的相互作用。
The behavior of single layer van der Waals (vdW) materials is profoundly influenced by the immediate atomic environment at their surface, a prime example being the myriad of emergent properties in artificial heterostructures. Equally significant are adsorbates deposited onto their surface from ambient. While vdW interfaces are well understood, our knowledge regarding atmospheric contamination is severely limited. Here we show that the common ambient contamination on the surface of: graphene, graphite, hBN and MoS2 is composed of a self-organized molecular layer, which forms during a few days of ambient exposure. Using low-temperature STM measurements we image the atomic structure of this adlayer and in combination with infrared spectroscopy identify the contaminant molecules as normal alkanes with lengths of 20-26 carbon atoms. Through its ability to self-organize, the alkane layer displaces the manifold other airborne contaminant species, capping the surface of vdW materials and possibly dominating their interaction with the environment.
