9527814 Kummel This research project is an effort to understand basic halogen chemistry on GaAs, and the correlations between surface chemistry, structure and electronic properties. Additionally, the project includes an activity to apply the results of the chemical passivation study to device fabrication with development of a gate insulator of CaF2 or SrF2 and a halogen passivated, un-pinned GaAs surface. For basic passivation studies an atomic passivation layer will be formed by dosing of F2, Cl2, Br2, I2 with a differentially pumped MBE source and cycling the substrate temperature to remove arsenic halides or gallium polyhalide from the surface. Samples will be characterized in an STM chamber with XPS and STM used to detect the position of the Fermi level within the bandgap. %%% The knowledge and understanding gained from this research project is expected to contribute in a fundamental way to improving the performance of advanced compound semiconductor materials used in computing, information processing, and telecommunications by providing a fundamental understanding and a basis for designing and producing improved layered structures of materials required for advanced devices and circuits. 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. ***
