Observation and control of adsorbed molecules

Abstract

Molecular movement induced by an electric field was observed by scanning tunneling microscopy. The observed feature of the molecular lines of liquid crystal 4‐hexyl‐4’‐cyanobiphenyl on graphite appeared to change drastically in 2 min after the polarity inversion of the bias voltage, together with small shifts in the lateral arrangement of individual molecules. The rearrangements took place at the bias voltage at around 2 V and the process was found to be reversible. When a bias voltage less than −2.8 V was applied to the tip, an irreversible process, the deposition of molecules, occurred. The minimum deposition size was about 20 nm and was found to be determined by the tip shape.