Adsorption and absorption of Boron, Nitrogen, Aluminium and Phosphorus on Silicene: stability, electronic and phonon properties

TL;DR

This study uses ab initio density-functional theory to explore how B, N, Al, and P atoms adsorb onto silicene, revealing stable, metallic, and chemically reactive modifications with distinct electronic and vibrational properties.

Contribution

It provides detailed insights into the preferred adsorption sites, electronic behavior, and vibrational characteristics of silicene functionalized with these atoms, highlighting its reactivity and potential for functionalization.

Findings

All adsorbed systems are metallic with significant electron transfer.

Stable up to 500 K, indicating thermal robustness.

Distinct phonon signatures suggest Raman detection of functionalization.

Abstract

Ab initio calculations within the density-functional theory formalism are performed to investigate the chemical functionalization of a graphene-like monolayer of silicon - silicene - with B, N, Al or P atoms. The structural, electronic, magnetic and vibrational properties are reported. The most preferable adsorption sites are found to be valley, bridge, valley and hill site for B, N, Al and P adatoms, respectively. All the relaxed systems with adsorbed/substituted atoms exhibit metallic behaviour with strongly bonded B, N, Al, and P atoms accompanied by an appreciable electron transfer from silicene to the B, N and P adatom/substituent. The Al atoms exhibit opposite charge transfer, with n-type doping of silicene and weaker bonding. The adatoms/substituents induce characteristic branches in the phonon spectrum of silicene, which can be probed by Raman measurements. Using molecular dynamics we found that the systems under study are stable up to at least T = 500 K. Our results demonstrate that silicene has a very reactive and functionalizable surface.