Structure function relationship in electronic thin films

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The proposed research is about the structure-function relationship of two types of thin films: one is made of organic semiconducting molecules and the other is made of metal silicide. The interest in both types of films lies in their functional properties for electronic applications. The metal silicides of our interest are for making electrical connection leads and gate pads in the advanced silicon-based integrated circuits. For device dimensions down to several dozen nanometers, a detail understandings of the film atomic structures is required. The organic thin films are used as active semiconductor layers in field-effect transistor and light emitting transistor applications. The advantages of organic electronics include low fabrication cost, large area and devices on flexible substrates. In these field effect devices the device performance relies on the orderliness of molecules in few molecular layers at the interface between organic semiconductor and gate insulator, a region of few nanometers in thickness. Our research is to characterize the atomic or molecular structures in these nanometer scale regions of interest, and base on the structural understanding to improve the film formation process towards the desired functional properties. Our primary tool for investigating these nanoscale films is X-rays of various wavelength, generated by the synchrotron accelerator at the Canadian Light Source. We also use the Advanced Photon Source in the States, using the pacific northwest consortium facilities participated by Canadian institutions. Experimentally we use a combined approach including X-ray absorption spectroscopy (extended X-ray absorption fine structure and near edge X-ray absorption fine structure), grazing-incidence X-diffraction and X-ray scattering techniques to probe the nanoscale structures. The metal silicide films are formed by solid state reactions by our collaborators. The organic semiconductor films are fabricated in our laboratories at Guelph using vacuum vapor deposition techniques, assisted with atomic force microscope imaging techniques to ensure the morphological integrity of the samples and photoelectron spectroscopy techniques for their chemical composition integrity.