Title:
III-V Nitride Based Micro and Nanoscale Sensors
III-V Nitride Based Micro and Nanoscale Sensors
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Author(s)
Koley, Goutam
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Abstract
Structural, mechanical, and sensing properties of InN nanowires (NWs) grown by chemical vapor deposition process have been
investigated for their applications in nanoscale sensors. It has been observed that the NWs bend spontaneously or upon meeting an
obstacle in their growth path at angles that are multiples of 30°. Lithographically patterned barriers served as guides for the NW growth,
which depending on the angle of incidence of the NW, made them grow along the barrier or get deflected from it. Diameter dependent
electrical properties of InN nanowires (NWs) grown by chemical vapor deposition were also investigated. InN NW based back-gated
field effect transistors (FETs) showed excellent gate control and drain current saturation behaviors. Both NW conductance and carrier
mobility calculated from the FET characteristics were found to increase regularly with decrease in NW diameter, with values of ~1000 cm²/Vs and ~1050 S/cm, observed respectively, for a 12 nm diameter NW. The observed mobility and conductivity variations have been
modeled by considering NW surface and core conduction paths. InN NWs grown with thick In₂O₃ shell layer demonstrated NO₂
detection capability down to 45 ppb in a field effect transistor configuration. Overall, the structural and electrical properties of the
NWs are found to be highly suitable for applications in nanoscale sensors and nanoelectromechanical systems. AlGaN/GaN
heterostructure based microcantilever sensors on Si (111) substrate are also being developed at USC for harsh environment sensing
applications. Initial fabrication and characterization results indicate very high sensitivity for these sensors.
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Date Issued
2011-03-08
Extent
62:54 minutes
Resource Type
Moving Image
Resource Subtype
Lecture