Investigation of surface morphology, optical and electronic properties of Mg2Si thin films on Si(111)

Abstract

The article presents the results of a study of the elemental composition, surface morphology, optical and electronic properties of Mg2Si thin films formed on Si (111). Both samples containing films were formed in layers by the method of reactive epitaxy, but at different heating temperatures of the substrates. The formed films consisting of alternating layers of Mg and Si at a ratio of 3:1, according to electron Auger spectroscopy, contain Mg and Si atoms in the associated layers. The Raman light scattering method established the presence of peaks on the graphs of samples at a shift of 258 and 348cm-1 belonging to Mg2Si. Infrared spectroscopy data also indicate the presence of magnesium silicide in the films. The thickness of Mg2Si films was estimated from the data of the known dependence of the amplitude of absorption peaks at 272 cm-1 on the absorption coefficient, which gave the values of the thicknesses of the grown films. Based on the results of the study of samples in the infrared-ultraviolet range and on the basis of geometric calculations, the width of the Mg2Si band gap was determined.

Keywords

• magnesium silicide
• thin films
• reactive epitaxy
• surface morphology
• atomic force microscopy
• optical spectroscopy
• band gap
• indirect and direct transitions