CPM Seminar

Electronic transport in nanowires: from injection-limited to space-charge-limited behavior

François Léonard

Materials Physics Department
Sandia National Laboratories

Semiconductor nanowires show promise as active elements in electronic, optoelectronic, and sensing devices. To realize this promise, a fundamental understanding of their electronic transport properties is necessary. In this presentation, I will discuss recent work that couples experiment and theory to discover and elucidate unusual electronic transport behavior in semiconducting nanowires. Two examples will be given: in GaN nanowires, we achieve efficient charge injection and find that space-charge-limited currents are unusually strong because of the reduced dimensionality. In contrast, charge transport across individual Au-nanoparticle/Ge-nanowire interfaces is injection-limited, and surprisingly, the conductance of these nanocontacts increases as the nanowire diameter is decreased. This behavior arises due to a dominance of electron-hole recombination, contrary to common expectations. More generally, our results indicate that dimensionality effects govern the properties of semiconducting nanowires even at sizes where quantum effects are unimportant.