Axial p-n Nanowire Gated Diodes as a Direct Probe of Surface-Dominated Charge Dynamics in Semiconductor Nanomaterials

Axially doped p-n silicon nanowire (SiNW) gated diodes are fabricated, and their electrical properties are investigated to demonstrate the enhanced surface effects on the nanoscale devices of semiconductor nanomaterials. The fabricated p-n SiNW exhibited clear rectifying characteristics with an ideality factor of similar to 2. More interestingly, the gated p-n SiNW showed a switching behavior as a function of the gate bias with almost complete turn-off of the forward current. The observed ideality factor and gated diode characteristics were explained with surface trap states of the nanowires. Systematic 3D device simulation quantitatively confirms that the surface states are a key factor in determining such surface-dominated characteristics. This work would serve the fundamental and in-depth understanding of the surface properties in the various nanoscale 1D devices.