Interfaces in Organic Thin Film Transistors

University Of Rochester, Rochester NY

Investigators

Abstract

The goal of this proposal is achieve fundamental understanding though detailed interface analysis of existing and novel organic/inorganic and organic/organic structures relevant to the development of organic based thin film transistors(OTFT). The approach is to probe in detail the interface properties in model OTFT structures/devices. Attention will be focused on electronic structures, chemical reactions, interdiffusion, and charge transfer of the organic/metal, organic/organic and organic/dielectric interfaces from a microscopic or atomic viewpoint. The interface analysis will be coordinated with morphological and basic electrical characterization of the OTFTs. The objective is to provide a better understanding of the fundamental aspects of interface properties of organic semiconductors and to relate this interface knowledge to next generation OTFTs. Surface/interface analytical tools include x-ray photoemission spectroscopy (XPS), ultraviolet photoemission spectroscopy (UPS), inverse photoemission spectroscopy (IPES), near edge x-ray absorption fine structure (NEXAFS), and low energy electron diffraction (LEED). The interface/surface analysis will be supported by structural and electronic characterization, including atomic force microscopy (AFM), scanning capacitance-voltage (SCV), scanning tunneling microscopy (STM), and scanning tunneling spectroscopy (STS). The analysis will also be supplemented with device characterizations, including basic electrical characterization, internal photoemission, and electroabsorption. With controlled vapor deposition and in situ sputtering in an ultra-high vacuum (UHV) environment, the interface will be constructed by deposition of a monolayer or sub-monolayer at a time, and the electronic, chemical, and morphological structures will be monitored with surface/interface analytical tools as the interface is being formed. %%% The project addresses basic research issues in a topical area of materials science with high technological relevance. Experimental tools are now available to allow atomic level observation of elementary surface processes which when better understood allow advances in fundamental science and technology. The basic knowledge and understanding gained from the research is expected to contribute to improving the perform-ance and stability of advanced devices and circuits by providing a fundamental understanding and a basis for designing and producing improved materials, and materials combinations. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area. ***