Tip-induced oxidation of silicene nano-ribbons

TL;DR

This study investigates the oxidation behavior of silicene nanoribbons on Ag(110), revealing their resistance to molecular oxygen and reactivity to atomic oxygen, with oxidation controllable via electric field and oxygen type.

Contribution

It demonstrates the electric field threshold for oxygen dissociation on silicene nanoribbons and compares their reactivity to molecular versus atomic oxygen.

Findings

Silicene nanoribbons resist oxidation by molecular oxygen.

Atomic oxygen readily oxidizes silicene nanoribbons.

Oxidation can be controlled by electric field and oxygen type.

Abstract

We report on the oxidation of self-assembled silicene nanoribbons grown on the Ag(110) surface using Scanning Tunneling Microscopy and High-Resolution Photoemission Spectroscopy. The results show that silicene nanoribbons present a strong resistance towards oxidation using molecular oxygen. This can be overcome by increasing the electric field in the STM tunnel junction above a threshold of +2.6 V to induce oxygen dissociation and reaction. The higher reactivity of the silicene nanoribbons towards atomic oxygen is observed as expected. The HR-PES confirm these observations: Even at high exposures of molecular oxygen, the Si 2p core-level peaks corresponding to pristine silicene remain dominant, reflecting a very low reactivity to molecular oxygen. Complete oxidation is obtained following exposure to high doses of atomic oxygen; the Si 2p core level peak corresponding to pristine silicene disappears.