“InSb-Based Heterostructures for Electronic Device Applications”
Michael Santos, University of Oklahoma
Abstract
In narrow-gap semiconductors, electrons have properties that are much different than in GaAs or Si. For example, the effective mass of electrons in InSb is two orders of magnitude smaller than the mass in free space. This property can be exploited in electronic device applications, including field-effect transistors, magnetic-field detectors and ballistic transport devices, where a high mobility or a long mean free path is required. The strength of the interaction between an electron’s spin and a magnetic field is also enhanced in InSb. The consequences of a small effective mass and large spin-orbit coupling are seen in far-infrared spectroscopy and charge transport measurements performed on structures with nanometer-scale dimensions in one or more directions.
Crystalline defects, due to growth on lattice-mismatched GaAs substrates, are an important factor limiting the electron mobility in InSb/AlxIn1-xSb heterostructures. InSb quantum-well structures with the highest room-temperature mobility (40,000 cm2/Vs) employ AlxIn1-xSb interlayers to reduce the density of threading dislocations. We have also produced p-type InSb quantum-well structures for potential use in digital circuits that require both p-type and n-type devices. The effects of strain and confinement on the effective mass of holes in InSb quantum wells are seen in magneto-optical experiments.
Bio
Michael Santos is a professor of physics and the Charles L. Blackburn Chair in Engineering Physics at the University of Oklahoma. Before joining the OU faculty in 1993 he was a postdoctoral researcher at AT&T Bell Laboratories. He has a Ph.D. in electrical engineering from Princeton and a B.S. in electrical engineering and materials science from Cornell. His research group at OU has co-authored 85 publications on the epitaxial growth and electronic properties of narrow-gap semiconductors.
