Construction Of Organic Photoelectric Monolayers On Silicon

More and more attention has been paid to hybrids of semiconductor materials, because they can not only combine different properties of organics and inorganics, but also gain new properties that neither organics nor inorganics have. Flexibility, processability, low cost, interesting optical-electric properties and so on make organic materials be a good substitute for inorganic ones. Modification of inorganics by organics can change surface properties of inorganics, for example, frictional, optical, electrical, chemical and biocompatible properties. On the other hand, many interests have been shown to integration of functional organics in Si-base devices because of their great promise in optoelectronic, micro-electronic and sensor applications.In this paper, stable perylene and phthalocyanine monolayers were obtained through modifying silicon wafers by chemical reaction between organic macrocycle molecules and functional silicon surface. The surface morphology, aggregation and optical-electric properties of these monolayers were characterized by XPS, FTIR, UV-Vis spectrum, AFM, Raman, XRD and Surface photovoltaic spectrum.FTIR and XPS proved that PTCDA and TCPc were attached on the surface of silicon by covalent; AFM and UV-Vis showed PTCDA and TCPc arranged orderly on surface of silicon; Through Raman spectrum, we found that macrocycle molecules stand on surface of silicon, while macrocycle molecules in film by vacuum deposition parallel to silicon surface. Monolayer altered the properties of the surface of silicon in that it made the surface more attractive to PTCDA or TCPc. Surface photovoltaic spectrum and XPS showed the charges transfer occured in the interface between the perylene monolayer and silicon leading to strong photovoltaic response in 300~400nm.In addition, a kind of perylene derivative with pyridine group was synthesized, which made preparation for self-assemble of perylene mutilayers on silicon.All the results are of great importance to surface modification of inorganic semiconductor devices and integration of organic devices.