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Facilities
MBE
 Research
on InSb-based heterostructures began in 1993 with the installation of
an Intevac Gen II MBE system. Samples can be transferred under ultrahigh
vacuum conditions between three chambers: (1) a growth chamber for III-V
materials, (2) a growth chamber for IV-VI and fluoride materials, and
(3) a surface analysis chamber equipped for Auger Electron Spectroscopy
and X-ray Photoelectron Spectroscopy. A fourth chamber, for scanning probe
microscopy, will be added in 1999.
 The
III-V growth chamber is dedicated to materials formed from In, Ga, Al,
and Sb. Si is used as an n-type dopant. Effusion cells for As (for GaAs
buffer layers) and Be (for p-type doping) have recently been installed.
Our research, so far, has focused on the fabrication of InSb quantum wells
with AlxIn1-xSb barriers remotely doped with Si. Such structures enable
the study of the low-temperature properties of two-dimensional electron
systems with a low-effective mass, a high g-factor, and a non-parabolic
dispersion relation. The unusually high electron mobility in InSb quantum
wells at room temperature can potentially lead to improved magnetoresistive
sensors and faster transistors.
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