Scanning Probe Microscopy of Semiconducting Nanowires

A liquid He cooled scanning probe microscope (SPM) with a conducting tip has been used to image conduction through InAs and InP nanowires. The nanowires, grown using a vapor-liquid-solid technique, have diameters between 50 nm and 100 nm and resistances on the order of 10 k$\Omega $. Ti/Al electrodes were defined using e-beam lithography to form source and drain contacts with a spacing of 1 to 3 $\mu $m. The charged SPM tip is scanned in an area above the nanowire; the resulting change in nanowire conductance is recorded to form the image. These conductance images are used to study the behavior of electrons in the nanowire on a local scale.