N-Heterocyclic carbenes (NHCs) are promising modifiers and anchors for surface functionalization and offer some advantages over thiol-based systems. Because of their strong binding affinity and high electron donation, NHCs can dramatically change the properties of the surfaces to which they are bonded. Highly ordered NHC monolayers have so far been limited to metal surfaces. Silicon, however, remains the element of choice in semiconductor devices and its modification is therefore of utmost importance for electronic industries. Here, a comprehensive study on the adsorption of NHCs on silicon is presented. We find covalently bound NHC molecules in an upright adsorption geometry and demonstrate the formation of highly ordered monolayers exhibiting good thermal stability and strong work function reductions. The structure and ordering of the monolayers is controlled by the substrate geometry and reactivity and in particular by the NHC side groups. These findings pave the way towards a tailor-made organic functionalization of silicon surfaces and, thanks to the high modularity of NHCs, new electronic and optoelectronic applications.

N-杂环卡宾 (NHCs) 是用于表面功能化的有前途的改性剂和锚定剂，并且与基于硫醇的系统相比具有一些优势。由于其强大的结合亲和力和高电子捐赠，NHC 可以显着改变它们所结合的表面的特性。到目前为止，高度有序的 NHC 单分子层仅限于金属表面。然而，硅仍然是半导体器件的首选元素，因此它的改性对电子工业至关重要。在这里，对 NHCs 在硅上的吸附进行了综合研究。我们发现以直立吸附几何形状共价结合的 NHC 分子，并证明形成高度有序的单分子层，表现出良好的热稳定性和强大的功函数降低。单层的结构和排序由底物几何形状和反应性控制，特别是由 NHC 侧基控制。这些发现为硅表面的定制有机功能化铺平了道路，并且由于 NHC 的高度模块化，新的电子和光电应用。