Temperature-Dependent Growth and Evolution of Silicene on Au Ultrathin Films—LEEM and LEED Studies

Abstract

The formation and evolution of silicene on ultrathin Au films have been investigated with low energy electron microscopy and diffraction. Careful control of the annealing rate and temperature of Au films epitaxially grown on the Si(111) surface allows for the preparation of a large scale, of the order of cm2, silicene sheets. Depending on the final temperature, three stages of silicene evolution can be distinguished: (i) the growth of the low buckled phase, (ii) the formation of a layered heterostructure of the low buckled and planar phases of silicene and (iii) the gradual destruction of the silicene. Each stage is characterized by its unique surface morphology and characteristic diffraction patterns. The present study gives an overview of structures formed on the surface of ultrathin Au films and morphology changes between room temperature and the temperature at which the formation of Au droplets on the Si(111) surface occurs.

Silicene growth mechanisms on Au(111) and Au(110) substrates

“…However, another work, combining experimental and DFT investigations, concluded that the structure of silicene epitaxially grown on Au(111) substrate is in fact planar, thereby not presenting a significant level of buckling [14]. Additionally, recent experimental works have demonstrated the possibility of the coexistence of a low-buckled and planar phase of silicene when grown on Au(111) [48,49]. It is noteworthy that the works referenced [14,48,49] used a surface segregation technique to grow silicene, in contrast to the more common molecular beam epitaxy (MBE) approach applied to other substrates [14].…”

Epitaxial growth and structural properties of silicene and other 2D allotropes of Si

“…136 Annealing in the 420-535 K temperature range leads to the formation of hexagonal phases with a different lattice constant a 0 , which were assumed to correspond to low-buckled silicene layer (a 0 = 3.85 Å), and planar silicene (a 0 = 4.34 Å) developing above the low-buckled phase and separated from it by sparsely distributed Au atoms. Dewetting of the Au lm occurs for annealing above 540 K. 136 Thus, the Si/Au(111) system is extremely complex, due to the presence of numerous metastable bulk silicide phases. Quantitative structural characterizations are thus needed to determine the exact nature of the ordered phases observed.…”

Photoinduced spin-polarized transport and controllable valley-triplet pairing states in a silicene-superconductor junction

“…As far as the practical realization of such a silicene-SC hybrid structure is concerned, it should be possible to fabricate such a geometry with the currently available experimental techniques. Recently, silicene sheet has been successfully synthesized via epitaxial growth on Ag(111) and even on the nonmetallic substrate [39][40][41][42]. The typical spin-orbit energy in silicene is λ so ∼ 4 meV and the buckling parameter is 2l ≈ 0.46 Å.…”