个人简介

2003 Faculty Senate Teaching Award in the Sciences 1997 Faculty Award- UCSD Office for Students with Disabilities 1996 Editorial Advisory Board, Langmuir 1992 Yale University Science and Engineering Alumni Award for The Advancement of Basic and Applied Science 1990 David and Lucille Packard Fellow 1988 Postdoctoral position, Cornell University

研究领域

Physical/Analytical Chemistry

As semiconductor devices decrease in size to atomic dimensions, an atomic level knowledge of the interfaces in semiconductors device is required. We combine the vapor deposition of oxides and organic semiconductors with scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), and density functional theory (DFT) computations to develop a fundamental understanding of the chemistry and physics of semiconductor interfaces. Atomic Structure of Interfaces of Gate Oxides on Semiconductors: As semiconductor gate lengths shrink below 150 nm, the gate oxides must become thinner and have a higher dielectric constant. Our group is studying deposition processes and bonding structures that result in electrically passive interfaces between high-k oxides and many semiconductors surfaces. By studying the adsorption of Ga2O, In2O, SiO, O, and O2 on GaAs(001) STM, STS, and DFT calculations, we have been able to obtain an atomistic understanding of Fermi level pinning and unpinning at the GaAs(001)/oxide interface. Current aspects of this project include (a) oxides interfaces on InAs which has over 20x the electron speed of silicon, (b) oxide interfaces on AlGaAs which is used in InP devices, (c) oxide interfaces on Ge which has over 4x the hole speed of silicon, and (d) cross sectional STM of oxide-semiconductor interfaces. Chemical Sensing with Metal Phthalocyanines: Metal phthalocynaines (MPcs) can be used as the carrier layer in transistors (ChemFETs) to fabricate a gas sensor with very high sensitivity (ppb) because MPcs change from insulating to semiconducting upon gas absorption. We are studying the formation of the MPcs films and gas adsorption on MPcs with STM. In addition, we are using vacuum deposition to form gas sensors with MPcs.

近期论文

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Comparison of density functional theory methods as applied to compound semiconductor-oxide interfaces. With S. I. Yi, M. Hale, and J. Sexton. J. Vac. Sci. Technol. B21(4) (2003). Direct and Precursor Mediated Hyperthermal Abstractive Chemisorption of Cl2/Al(111). With G. C. Poon, T. J. Grassman, and J. C. Gumy. J. Chem. Phys. (2003) in press. Scanning Tunneling Microscopy and Spectroscopy of Gallium Oxide Deposition on GaAs(001)-(2x4). With J. Sexton. J. Chem. Phys. (2003) in press. Orientation dependent charge transfer and chemisorption reaction. With A. J. Komrowski, H. Ternow, B. Razaznejad, B. Berenbak, J. Z. Sexton, I. Zoric, B. Kasemo, B.I. Lundqvist, S. Stolte, and A. W. Kleyn. J. Chem. Phys. 117, 8185 (2002). Self aligned GaAs p-channel enhancement mode MOS heterostructure field-effect transistor. With M. Passlack, J.K. Abrokwah, R. Droopad, Z.Y. Yu, C. Overgaard, S.I. Yi, M. Hale, and J. Sexton. IEEE Elect. Device Lett. 41, 3226 (2002). Adsorption of atomic oxygen on GaAs(001)-(2*4) and the resulting surface structures. With S. I. Yi, P. Kruse, and M. Hale. J. Chem. Phys. 114, 3215 (2001). Chemically selective adsorption of molecular oxygen on GaAs(100)-c(2x8). With P. Kruse and J. G. McLean. J. Chem. Phys. 113, 9224 (2000).