Molecular layer epitaxy method and compositions

A method of forming a multi-layered structure composed of two or more discrete monomolecular layers, where each layer is composed of molecules of a selected polycyclic aromatic compound having a defined axis oriented substantially normal to the plane of the monolayer, said method comprising one or more repetitions of:

• depositing molecules of a selected polycyclic aromatic compound having a defined axis with a chemically reactive group at each axial end, by vapor phase deposition, onto a substrate having surface-reactive sites capable of reacting with the chemically reactive group in the selected compound, said depositing being carried under conditions which allow chemiadsorption of the selected compound in a molecular monolayer, by covalent coupling of one end of the compound to the substrate, and sublimation of non-covalently bonded compounds from the surface;
• and
• by said depositing, forming on the substrate, a monomolecular layer of the selected compound;
• wherein each repetition forms a new substrate having a surface-exposed monolayer with exposed reactive groups.

A method of forming a multi-layered structure composed of two or more discrete monomolecular layers, where each layer is composed of molecules of a selected polycyclic aromatic compound having a defined axis oriented substantially normal to the plane of the monolayer, said method comprising:

• providing a solid surface having surface reactive sites;
• depositing on said solid surface a selected coupling agent having a first reactive group, which is capable of reacting with the reactive sites of the said solid surface;
• and a second reactive group, which is capable of reacting neither with the reactive sites of the said solid surface nor with the said first reactive group;
• by said deposition, forming a substrate having surface reactive sites, the substrate being composed of the said solid surface and a template layer chemiacsorbed thereon by covalent coupling of the first reactive group of the coupling agent to the reactive sites of the said solid surface;
• the surface reactive sites of the substrate are occupied with the second reactive group of the said coupling agent;
• depositing on said template layer molecules of a selected polycyclic aromatic compound having a defined axis with a chemically reactive group at each axial end, by vapor phase deposition, said selected polyciclic aromatic molecules being capable of reacting with the second reactive groups exposed on the said substrate, said depositing being carried under conditions which allow chemiadsorption of the selected compound in a molecular monolayer, by covalent coupling of one end of the compound to the template layer, and sublimation of non-covalently bonded compounds from the surface;
• and
• by said depositing, forming on the template layer a monomolecular layer of the selected compound to form a substrate having a surface-exposed monolayer with exposed reactive groups;
• repeating one or more repetitions of
• depositing molecules of a selected polycyclic aromatic compound having a defined axis with a chemically reactive group at each axial end, by vapor phase deposition, onto the said substrate having a surface-exposed monolayer with exposed reactive groups;
• wherein said chemically reactive groups of said selected polycyclic aromatic compound is capable of reacting with the chemically reactive groups of said substrate, said depositing being carried under conditions which allow chemiadsorption of the selected compound in a molecular monolayer, by covalent coupling of one end of the compound to the substrate, and sublimation of non-covalently bonded compounds from the surface;
• and
• by said depositing, forming on the substrate, a monomolecular layer of the selected compound;
• wherein each repetition forms a new substrate having a surface-exposed monolayer with exposed reactive groups.