Energetically Favored 2D to 3D Transition: Why Silicene Cannot Be Grown on Ag(111).
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38502098.
- Also identified by DOI 10.1021/acs.nanolett.4c00140 and PMC identifier 11010229.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Silicene, a two-dimensional (2D) Si monolayer with properties similar to those of graphene, has attracted considerable attention because of its compatibility with existing technology. Most growth efforts to date have focused on the Ag(111) substrate, with a 3 × 3 phase widely reported below one monolayer (ML). As the coverage increases, a √3 × √3 pattern frequently emerges, which has been proposed by various experimental investigations as a <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>Si</mi><mrow><mo>(</mo><mn>111</mn><mo>)</mo></mrow><mo>-</mo><msqrt><mrow><mn>3</mn></mrow></msqrt><mo>×</mo><msqrt><mrow><mn>3</mn></mrow></msqrt><mo>-</mo><mi>Ag</mi></math> reconstructed structure. We report first-principles calculations to understand this series of observations. A major finding from our energetics studies is that Si growth on Ag(111) beyond one ML will switch to the Volmer-Weber mode, forming three-dimensional sp<sup>3</sup> films. Combining with the condition that the 3 × 3 monolayer on Ag(111) does not have the correct buckling pattern of freestanding silicene, we conclude that silicene cannot be grown on Ag(111) and that a 2D to 3D transition is energetically favored beyond one ML.