Characterizations of Ohmic and Schottky-behaving contacts of a single ZnO nanowire
Abstract
Current–voltage and Kelvin probe force microscopy (KPFM) measurements were performed
on single ZnO nanowires. Measurements are shown to be strongly correlated with the contact
behavior, either Ohmic or diode-like. The ZnO nanowires were obtained by metallo-organic
chemical vapor deposition (MOCVD) and contacted using electronic-beam lithography.
Depending on the contact geometry, good quality Ohmic contacts (linear I–V behavior) or
non-linear (diode-like) contacts were obtained. Current–voltage and KPFM measurements on
both types of contacted ZnO nanowires were performed in order to investigate their behavior.
A clear correlation could be established between the I–V curve, the electrical potential profile
along the device and the nanowire geometry. Some arguments supporting this behavior are
given based on technological issues and on depletion region extension. This work will help to
better understand the electrical behavior of Ohmic contacts on single ZnO nanowires, for
future applications in nanoscale field-effect transistors and nano-photodetectors.