Avalanche breakdown in surface modified silicon nanowires

The electrical conductance of semiconductor nanowires can be changed by charges present on the nanowire surface. At high surface charge density, however, the nanowire channel may be quenched leading to a large shift in the IDS-VDS characteristics. In this letter, the authors demonstrate that this shift in VDS is related to an avalanche effect in the nanowire. Silicon nanowires were fabricated in a top-down approach and the nanowire surface charge density was modified through buffer solutions of different pH values. Computer simulations using representative surface charge and interface charge densities clearly reproduce the data and unambiguously demonstrate the avalanche effect.