Homer L. Dodge Department
of Physics and Astronomy
The University of Oklahoma

 

Since arriving at the University of Oklahoma in 1993, my research interests have focused on InSb-based heterostructures for electronic device applications. Because the bandgap of InSb is the smallest of all binary III-V compounds, two-dimensional electron systems (2DESs) in InSb quantum wells have several extreme properties: a small effective mass, a large g-factor, a high intrinsic mobility, and a non-parabolic dispersion relation. Using the department's molecular beam epitaxy (MBE) system, my research group fabricates InSb quantum-well structures with AlxIn1-xSb barrier layers. The room-temperature mobility in these structures is higher than in quantum wells made of any other semiconductor. We are exploring ways to exploit this feature in mesoscopic magnetoresistors, ballistic transport devices, and spin devices. Because of the extreme properties of InSb, the behavior of our 2DESs in the quantum Hall regime (low temperature and high applied magnetic field) differs from that observed in more commonly studied GaAs-based heterostructures. These fundamental studies are being pursued in collaboration with Professors Murphy (magneto-transport) and Doezema (far infrared magneto-optics), researchers at NTT Basic Research Laboratories in Japan, and others.

Since the operation of electronic devices depends on the material quality of the heterostructures, my group makes use of materials analysis techniques including transmission electron microscopy, reflection high-energy electron diffraction, Auger electron spectroscopy, x-ray photoelectron spectroscopy, high-resolution x-ray diffraction, and scanning probe microscopy. Some of these materials studies are performed in collaboration with Professor Johnson's group.