Low temperature formation of Si(111)-(2n+1) x (2n+1) surface reconstructions

Scanning tunneling microscopy was used to study the surface morphology changes of the H-terminated Si(111) surface during Ag deposition at elevated temperatures. Flat H-terminated Si(111) surfaces were prepared by NH4F etching. Domains of various dimer-adatom-stacking-fault superstructures, such as 3 x 3, 5 x 5, 7 x 7, and 9 x 9 were observed on the Si(111) surface after hot deposition of 1 ML Ag at 550 degreesC. This phenomenon was compared with hydrogen thermal desorption experiments, which did not show the formation of metastable surface superstructures at temperatures near 550 degreesC. All metastable superstructures obtained after hot Ag deposition at 550 degreesC were found to convert into the 7 x 7 reconstruction after annealing at 600 degreesC. (C) 2002 Elsevier Science B.V. All rights reserved.