Advisor: R. F. Davis, MSE.
To achieve stable operating conditions, long equipment life, high efficiency,
and low pollution levels during the operation of turbine combustion systems the
in-situ measurement of the composition of natural gas or syngas is required. The
most common of the gas constituents are CH4, C2H6, C3H8, and H2. The optimum
dissociation temperatures of these hydrocarbon gases and H2, via catalysis, is
between 300 and 600°C. As such, the intrinsic wide band gap, high electric
field strength and chemical inertness of GaN and AlGaN alloys make them advantageous
materials for sensing devices that must operate at high temperatures in chemically
aggressive environments. In addition, GaN material technologies have become
sufficiently mature that both n- and p-type materials are commercially common. It
is from these materials that AlGaN/GaN high-electron-mobility transistors (HEMTs)
are being developed as sensors of the gases noted above prior to combustion. The
REU students involved in this program will be trained to operate state-of-the-art
chemical vapor deposition systems for the growth of the SiC- and AlGaN/GaN-based
films that compose the material device structures. These students will
also employ atomic force and electron microscopies to determine the surface microstructures
of the surfaces of the substrates and the subsequently grown films that compose
the HEMT devices. In addition, the students will electrically characterize
the devices.
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