On-Surface Oligomerization of Self-Terminating Molecular Chains for the Design of Spintronic Devices.

Molecular spintronics is currently attracting a lot of attention due to its great advantages over traditional electronics. A variety of self-assembled molecule-based devices are under development, but studies regarding the reliability of the growth-process remain rare. Here, we present a method to control the length of molecular spintronic chains and to make their terminations chemically inert, thereby suppressing uncontrolled coupling to surface defects. The temperature evolution of chain formation was followed by X-ray photoelectron spectroscopy, to determine optimal growth conditions. The final structures of the chains were then studied, using scanning tunneling microscopy, as a function of oligomerization conditions. We find that short chains are readily synthesized with high yields, and that long chains, even exceeding 70 mers, can be realized under optimized growth parameters, albeit with reduced yields.