Atomic scale understanding of linear and perpendicular junction of molecular lines on Si(100)-H surface

Fabrication of both linear and perpendicular junctions of one-dimensional molecular assembly (molecular line) on Si(100)-(2 × 1)-H surface and it´s fine structure have been investigated using scanning tunneling microscope (STM) at 300 K. The end-molecule of a styrene line appears brighter than other molecules of the line in STM image after forming a perpendicularly connected allylmercaptan line. The observed changes in image height of the end-molecule after junction formation is ascribed to the shifting of frontier energy states of the junction molecule by interaction with nearby allylmercaptan molecules. Unlike perpendicular junction, the molecule at linear junction consisting of benzophenone and 4,4´-dichlorobenzophenone lines do not show significant change compared to the bulk molecules. The alignments of the styrene molecules in a doubled molecular line are discussed.