MICHAEL B. WEIMER (Ph.D., California Institute of Technology, 1986)

UHV Scanning Tunneling Microscopy of Semiconductor Surfaces and Interfaces

Research in the Scanning Tunneling Microscopy (STM) Laboratory at Texas A&M is aimed at developing a comprehensive experimental picture of the structure and electronic properties of III-V semiconductor surfaces and interfaces. Our early studies emphasized classic problems in surface science, such as the dynamics of surface vacancies and the bonding geometry of adsorbed molecules. More recent work has taken advantage of the nanometer-scale spatial resolution afforded by STM to advance our understanding of two especially significant problems in III-V epitaxial growth: the precise structure of the interfaces in type-II semiconductor superlattices and quantum wells, and the onset of atomic ordering in III-V semiconductor alloys.

	Optical Science and Technology Center - University of Iowa
	Air Force Research Laboratory
	MIT Lincoln Laboratory
	HRL Laboratories
	National Renewable Energy Laboratory
	Space Vacuum Epitaxy Center - University of Houston

POSITION ANNOUNCEMENTS

• Postdoctoral Research Associateship (description)
  Available: Early 2001

• Graduate Research Assistantship
  Available: Fall 2001

• George Alan Lengel, Ph.D. 1995
  Doctoral Dissertation: Structure and Dynamics of Vacancies on GaAs(110) Studied by Scanning Tunneling Microscopy
  Current Location: RHK Technology, Troy, Michigan

• Geoffrey Wayne Brown, Ph.D. 1997
  Doctoral Dissertation: The Reaction of Ammonia with GaAs(110) Studied by Scanning Tunneling Microscopy
  Current Location: Los Alamos National Laboratory, Los Alamos, New Mexico

• John Raymond Harper, Ph.D. 1999
  Doctoral Dissertation: Cross-Sectional Scanning Tunneling Microscopy Studies of Type-II Superlattices and Quantum Wells Grown by Molecular Beam Epitaxy
  Current Location: Raytheon, Dallas, Texas

• Jeremy David Steinshnider, Ph.D. 2002
  Doctoral Dissertation: Characterizing Interfacial Structure at Non-Common-Atom Heterojunctions with Cross-Sectional Scanning Tunneling Microscopy
  Current Location: Lynntech , College Station, Texas

• Cross-Sectional STM as a Probe of Atomic-Scale Order in III-V Semiconductor Alloys
  Centennial Meeting of the American Physical Society
  Atlanta, Georgia, March 1999.

• Characterizing Atomic-Scale Composition Variations in Epitaxial III-V Materials with Cross-Sectional STM
  Fall Meeting of the Materials Research Society
  Boston, Massachusetts, November 1999.

• Origin of Antimony Segregation in GaInSb / InAs Strained-Layer Superlattices
  J. Steinshnider, J. Harper, M. Weimer, C.-H. Lin, S.S. Pei, and D.H. Chow
  Phys. Rev. Lett. 85, 4562-4565 (2000).
  PDF (209k)

• Visualizing Interfacial Structure at Non-Common-Atom Heterojunctions with Cross-Sectional Scanning Tunneling Microscopy
  J. Steinshnider, M. Weimer, R. Kaspi, and G.W. Turner
  Phys. Rev. Lett. 85, 2953-2956 (2000).
  PDF (449k)

• Electrostatic Screening Near Semiconductor Surfaces
  M. Krcmar, W. Saslow, and M. Weimer
  Phys. Rev. B 61, 13821-13832 (2000).
  PDF (415k)

• An Adjustable Oxide-Free Tunnel Junction for Vibrational Spectroscopy of Molecules
  D. Zimmerman, M. Weimer, and G. Agnolet
  Appl. Phys. Lett. 75, 2500-2502 (1999).
  PDF (152k)

• Microstructure of the GaSb-on-InAs Heterojunction Examined with Cross-Sectional Scanning Tunneling Microscopy
  J. Harper, M. Weimer, D. Zhang, C.-H. Lin, and S.S. Pei
  Appl. Phys. Lett. 73, 2805-2807 (1998).
  PDF (810k)

• Charge Injection and STM-Induced Vacancy Migration on GaAs(110)
  G. Lengel, J. Harper, and M. Weimer
  Phys. Rev. Lett. 76, 4725-4728 (1996).
  PDF (374k)

• Scanning Tunneling Microscopy of the Reaction of NH₃ with GaAs(110)
  G. Brown and M. Weimer
  J. Vac. Sci. Technol. B 13, 1679-1683 (1995).
  PDF (467k)

• Geometry and Electronic Structure of the Arsenic Vacancy on GaAs(110)
  G. Lengel, R. Wilkins, G. Brown, and M. Weimer
  Phys. Rev. Lett. 72, 836-838 (1994).
  PDF (315k)

FEDERAL SPONSORS

• National Science Foundation

• Air Force Research Laboratory

• Office of Naval Research

 

Disclaimer

Any opinions, findings, or conclusions expressed in these materials are those of the authors and do not necessarily reflect the views of the National Science Foundation, Air Force Research Laboratory, or Office of Naval Research.