49 research outputs found
Correlating the nanostructure and electronic properties of InAs nanowires
The electronic properties and nanostructure of InAs nanowires are correlated
by creating multiple field effect transistors (FETs) on nanowires grown to have
low and high defect density segments. 4.2 K carrier mobilities are ~4X larger
in the nominally defect-free segments of the wire. We also find that dark field
optical intensity is correlated with the mobility, suggesting a simple route
for selecting wires with a low defect density. At low temperatures, FETs
fabricated on high defect density segments of InAs nanowires showed transport
properties consistent with single electron charging, even on devices with low
resistance ohmic contacts. The charging energies obtained suggest quantum dot
formation at defects in the wires. These results reinforce the importance of
controlling the defect density in order to produce high quality electrical and
optical devices using InAs nanowires.Comment: Related papers at http://pettagroup.princeton.ed
The growth and characterization of Si and Ge nanowires grown from reactive metal catalysts
We discuss the benefits of using metals other than Au to catalyze the growth of Si and Ge nanowires, emphasizing the opportunities that these non-conventional materials provide for tailoring electronic and structural nanowire properties. However, since these metals are more reactive than Au, their use creates constraints on wire growth conditions as well as difficulties in post-growth characterization. These issues are illustrated for Si and Si/Ge nanowires grown from Al, Cu and AuAl starting materials. The vacuum requirements for the deposition of the reactive metals are discussed as well as the effect of atmospheric exposure on the structure of wires observed post-growth with electron microscopy