Silicon surface functionalization targeting Si-N linkages.

Silicon substrates have been a fascinating topic of fundamental and applied research for well over 50 years. They have attracted even more attention over the last couple of decades with advances in chemical functionalization that made oxide-free silicon surfaces a reality. Fundamentally new electronic properties and chemical reactivity became available, and the focus of chemical research turned more toward targeting specific chemical bonds and functionalities on silicon. Although thermodynamics clearly drives most processes under ambient conditions toward the formation of an oxide layer, kinetic control of the oxidation processes and thermodynamic tricks based on gaining stability of surface monolayers with high-density assembly have allowed for the formation of stable Si-C bonds and Si-O-C linkages on oxide-free silicon crystals. This feature article targets recent advances in making Si-N linkages on the same oxide-free single crystals. It covers the range of chemical approaches to achieving this goal and offers possible chemistry that can take advantage of the systems produced. The present status of the field and the future directions of its development will be considered.