First steps of silicene growth on an insulating thin-film: effect of the substrate temperature

Abstract

Silicene is a two-dimensional (2D) material with very promising electronic properties for applications in silicon modern technology. However, the first experimental synthesis of silicene on metallic surfaces shows strong interactions between the silicene and its substrate, which can alter its electronic properties. Here, we report on the first steps of silicene growth on an insulating surface (NaCl) using scanning tunneling microscopy (STM), low energy electron diffraction (LEED), Auger electron spectroscopy (AES), and angle-resolved photoemission spectroscopy (ARPES). We demonstrate the importance of temperature annealing in the growth of silicene on NaCl. Indeed, after deposition of silicon on the NaCl/Ag(110) surface, we observe the following stages: i) at room temperature, the silicon atoms accumulate on top of the NaCl layer without any given order. ii) At 60°C, silicon dimers start to grow on the NaCl. iii) At 140°C, these dimers form a 2D silicon chains on the surface. iv) After a post-annealing at 200°C, evident 2D silicon nanoribbons with a honeycomb-like structure were observed. Our results of the first silicene growth stages on an insulating surface are a necessary step for exploring its growth mechanism further.