Structural and energy changes at the cleavage surfaces of In₄Se₃ layered crystals under interface formation

Abstract

Structural and energy changes at the cleavage surfaces of In₄Se₃ layered crystals during interface formation have been studied by means of the ultraviolet photo-electron spectroscopy (UPS) and low-energy electron diffraction. The unintentionally doped In₄Se₃ crystal cleavages exposed to atmosphere of ultrahigh vacuum chamber residual gases, treated by Ar ion sputtering and UV illumination show the differences in UPS spectra which might be attributed to transformations of electron energy structure of the surface. The analysis of the interface formation at In₄Se₃ cleavages is of importance due to the ability to obtain reliable results of the In₄Se₃ band mapping, avoiding the effect of the cleavage surface instability under UV, ion treatment and exposure to ultrahigh vacuum, that is unusual for layered crystals.