Electric field assisted electrochemical “writing” of Co nanostructures onto n-Si(111):H surfaces

Co nanostructures have been electrochemically grown on n-Si(111):H surfaces, making use of (i) inhibition of Co electrodeposition by the H-termination of n-Si(111):H surfaces and (ii) local modification of the H-termination by the electric field underneath a scanning tunneling microscope (STM) tip in tunneling contact, which enables localized Co electrodeposition. Movement of the STM tip at these conditions allows for continuous “writing” of structures a few nanometer wide and one to two monolayers high. The process is not in need of explicit H-desorption or formation of surface dangling bonds, and requires a minimum electric field of approximately 0.6 V/nm.

► Co nanostructures are electrochemically grown on n-Si(111):H surfaces. ► The electric field between STM tip and surface locally modifies the H-termination. ► Electric fields of approximately 0.6 V/nm allow for localized Co electrodeposition. ► Deposition is confined to dimensions of less than (6-8) nm. ► Moving the STM tip across the surface allows for a continuous “writing”.