Electrical transport in boron nanowires

Electrical transport is studied in crystalline boron nanowires, using Ni and Ti as the contact electrodes, in which Ni forms ohmic contact and Ti forms Schottky-barrier junction. Three-terminal electrical measurements demonstrate p-type semiconductor behavior with estimated carrier mobility of 10−3 cm2/V s. The conductivities in annealed devices are on the order of 10−2 (Ω cm)−1. At 4.2 K, the I-V shows low conductance at low bias voltage, and increases exponentially beyond a threshold electric field close to 105 V/cm. We attribute this behavior to electric-field-induced impact ionization.