Reversible Passivation of Silicon Dangling Bonds with the Stable Radical TEMPO

TEMPO, 2,2,6,6-tetramethylpiperidinyloxy, was used to passivate dangling bonds on hydrogen-terminated Si(100) and Si(111) surfaces. TEMPO reacts with the dangling bond through a radical coupling reaction of the oxygen and silicon atoms. STM images reveal that the TEMPO-passivated Si is stable under typical imaging conditions and also protects the surface from reaction with styrene. TEMPO may also be desorbed from the surface by scanning at elevated voltages (greater than −3.5 V) and provides the ability to selectively remove TEMPO to prepare single dangling bonds on an otherwise passivated surface.