Single-electron tunneling in InP nanowires

We report on the fabrication and electrical characterization of field-effect devices based on wire-shaped InP crystals grown from Au catalyst particles by a vapor–liquid–solid process. Our InP wires are $n$ -type doped with diameters in the 40–55-nm range and lengths of several micrometers. After being deposited on an oxidized Si substrate, wires are contacted individually via e-beam fabricated Ti/Al electrodes. We obtain contact resistances as low as $\text{∼10\hspace{0.17em}}\mathrm{k}\mathrm{\Omega ,}$ with minor temperature dependence. The distance between the electrodes varies between 0.2 and 2 μm. The electron density in the wires is changed with a back gate. Low-temperature transport measurements show Coulomb-blockade behavior with single-electron charging energies of $\text{∼1\hspace{0.17em}}\mathrm{meV}.$ We also demonstrate energy quantization resulting from the confinement in the wire.