Electrical Conduction Properties of Molecular Ultrathin Layers in a Nanocontact

The areas of nanoscience and nanoengineering have been developing very fast; a large range of nanoscale materials has been studied in view of various practical applications. Much work is performed in the area of innovating coatings. Such films require specific properties such as proper conduction and mechanical ones. These properties can be studied by conductive probe AFM (CP-AFM) techniques. These techniques have several advantages: they allow investigating electronic properties of the films at a micro/nano scale and also allow characterizing the films in a nanocontact situation taking into account mechanical effects. Ultra thin organic polyphenylene-like layers can be grafted on gold substrates and used as self-adhesive primers. Their electrical and mechanical properties were studied with a conductive probe AFM. Conduction properties were investigated by recording current-voltage characteristics. Simultaneous analysis of the electrical and mechanical properties was then performed during tip/sample approach and withdrawal in the so-called DRz mode of the CP-AFM. These DRz curves bring a good understanding of the evolution of the electrical properties with the applied load. Finally, an example of the use of these layers in the fields of nanoscience and electrical engineering is given, showing how these films can immobilize carbon nanomaterials such as graphene sheets and carbon nanotubes.