Growth of thin Sn films on Ag(111) studied with low-energy electron diffraction and X-ray photoelectron spectroscopy

• Published in: Thin solid films 2019-07, Vol.682, p.44-49
• Main Authors: Luh, Dah-An, Wang, Chia-Hsin, Yang, Yaw-Wen
• Format: Article
• Language: English
• Subjects: Low-energy electron diffraction; Silver; Thin films; Tin; X-ray photoelectron spectroscopy
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2019.04.047

Thin Sn films on Ag(111) grown at different Sn coverage and substrate temperature were characterized with low-energy electron diffraction and x-ray photoelectron spectra. The results show that surface alloying of Sn atoms on Ag(111) occurs at a temperature as low as 96 K, indicating a strong tendency to form a surface alloy between Sn and Ag. During the alloying, Sn atoms substitute Ag atoms in random locations, resulting in a disordered Sn/Ag(111) surface. The alloy surface becomes completely ordered with a (√3 × √3) R30° reconstruction (the √3 phase) only when it is annealed above 453 K, but annealing at 403 K converts all Sn atoms on Ag(111) into the alloy state; the surface coverage of Sn is no more than 1/3 monolayer with excess Sn diffusing into the Ag(111) substrate. These observations indicate that the √3 phase with the Sn-Ag surface alloy is the only ordered phase obtainable on Sn/Ag(111) once the Sn-Ag surface alloy is formed. It is consequently impracticable to grow non-alloy ordered phases, such as stanene, on Ag(111) epitaxially at a temperature above 96 K, showing evident discrepancies with the conclusions of the previous computational study. •Sn/Ag(111) thin films grown at different conditions are studied.•Sn-Ag alloying on Ag(111) occurs at a temperature as low as 96 K.•Annealing above 403 K converts all Sn atoms into alloy states.•Sn/Ag(111) has a completely ordered √3 phase only when annealed above 453 K.•Non-alloy ordered phases do not exist on Ag(111) when Sn is deposited above 96 K.