Studies of Interface Carbon Layer Formation on the Cleavage Surfaces of In4Se3 Layered Crystals by X-ray Photoelectron and Auger Electron Spectroscopy

Pavlo V. Galiy 1Anna V. Musyanovych 2Taras M. Nenchuk 1

1. Electronics Department, Lviv National University, 50 Dragomanov str., Lviv 79005, Ukraine
2. Dresden University of Technology, Institute of Macromolecular Chemistry and Textile Chemistry, 4 Mommsenstr, Dresden 01062, Germany

Abstract

XPS spectra were obtained for interface formation on the cleavage surfaces of In4Se3 layered semiconductor crystals that have been exposed in the air. Those exposed for 2-15 min are called fresh cleavages and those exposed for more than 24 hours are called the old cleavages.
The presence of the carbon on the fresh and old cleavage surfaces was shown using XPS analysis. The most intense XPS lines, viz. Se 3d, In 3d, C 1s, O 1s and the sharpest Auger lines were recorded in an expanded binding energy scale for the purpose of atomic concentration calculation and the charge transfer estimation. The exact peak position of these intense lines have been subsequently determined from the corresponding profiles, recorded on an expanded binding energy scale for Se 3d and In 3d. In each case Gausian line shape analysis has been done for the XPS expanded profiles after making the background correction using Shirley's method to determine the exact peak positions and peak areas. The chemical shifts have been calculated from the binding energy values of the XPS lines to Se, In, C and O, corrected with reference to vacuum level.
The strong decrease of the (O/C) and (N/C) ratios is observed in the case of the fresh, in comparison with the same ones for the old cleavages. This indicates, that in UHV chamber the adsorbed nitrogen is absent and carbon monoxide is the main adsorbate on the In4Se3 surface, and it forms In4Se3 -C interface.
The presence of non-simple interaction in the In4Se3 -C interfaces of old and fresh surfaces can be also confirmed by a closer inspection of the C 1s core level spectra. For the fresh cleavages of In4Se3 surface interface, the deconvoluted C 1s peak shows the presence of two types of carbon. They could be attributed to C-C (284.0 eV) and C-Se (284.39 eV). For the old In4Se3 surface interface, the presence of another carbon is detected at 284.39 eV attributed to C-C interaction in the "graphite phase".

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  1. Cleavage surfaces atomic and electronic structure of the layered In4Se3 crystals as natural 2D-materials

Presentation: poster at E-MRS Fall Meeting 2003, Symposium B, by Pavlo V. Galiy
See On-line Journal of E-MRS Fall Meeting 2003

Submitted: 2003-05-08 16:26
Revised:   2009-06-08 12:55
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