Interface Passivation and Trap Reduction via a Solution-Based Method for Near-Zero Hysteresis Nanowire Field-Effect Transistors

In this letter, we demonstrate a solution-based method for a one-step deposition and surface passivation of the as-grown silicon nanowires (Si NWs). Using <i>N</i>,<i>N</i>-dimethylformamide (DMF) as a mild oxidizing agent, the NWs’ surface traps density was reduced by over 2 orders of magnitude from 1 × 10<sup>13</sup> cm<sup>–2</sup> in pristine NWs to 3.7 × 10<sup>10</sup> cm<sup>–2</sup> in DMF-treated NWs, leading to a dramatic hysteresis reduction in NW field-effect transistors (FETs) from up to 32 V to a near-zero hysteresis. The change of the polyphenylsilane NW shell stoichiometric composition was confirmed by X-ray photoelectron spectroscopy analysis showing a 35% increase in fully oxidized Si<sup>4+</sup> species for DMF-treated NWs compared to dry NW powder. Additionally, a shell oxidation effect induced by DMF resulted is a more stable NW FET performance with steady transistor currents and only 1.5 V hysteresis after 1000 h of air exposure.