Observation of thin film of one‐dimensional organic conductor tetrathiofulvalene tetracyanoquinodimethane by means of atomic force microscopy

Thin films of the charge transfer complex of tetrathiofulvalene tetracyanoquinodimethane (TTF‐TCNQ) deposited on KC1 and KBr were studied by atomic force microscopy (AFM). Structures corresponding to the molecular arrangement of the crystallographic ab‐plane were observed in the molecular‐scale AFM images. Large‐scale imaging (15×15 μm) revealed that the films consist of rectangular islands whose longer sides (corresponding to the highly conductive b‐axis) orient in the [110] or [110] direction of the KC1 and KBr(001) surfaces. A small number of islands rotated 32° from the [110] direction were also observed on the KBr substrate. The arrangement of these islands can be explained by considering the adsorption of a TCNQ molecule to the metastable state.