XPS, AES AND UPS INVESTIGATION OF SnO₂/Si AND DFT-BASED THEORETICAL STUDY WITHIN THE mBJ-GGA SCHEME

Abstract

We investigate the growth performance of tin oxide on the Si substrate, achieved by spray pyrolysis using the sensitive analysis techniques X-Ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). These complementary techniques confirm the growth of homogeneous SnO2 thin films. We also study the electronic distribution of the valence band of SnO2 theoretically using density functional theory (DFT). The chemical and physical properties of the material depend on the electron structure varying as a function of energy. The density of states (DOS) is calculated using the modified Becke–Johnson-Generalized Gradient Approximation (mBJ-GGA) in order to identify the electronic orbitals and the importance of their contribution to the electronic structure of the valence band. Furthermore, we use the experimental technique UV Photoelectron Spectroscopy (UPS) for studying the electronic distribution within the valence band and for validating the theoretical results of the density of states of SnO2/Si.

Facile fabrication of defect-induced 2D-stanene/stanene-oxide nano-sheet structure material through etching of SnOx thin film by the process of successive Ar+ ion sputtering

“…This spectrum shows the classical doublet 3d 5/2 -3d 3/2 splitting peaks at 487.0 eV and 495.4 eV that can be assigned to the lattice tin in SnO 2 [1,2]. The 8.4 eV of the energy difference between Sn 3d 5/2 and Sn 3d 3/2 is in good agreement with the energy splitting reported for SnO 2 and the Sn 3d 5/2 peak is closely consistent with the standard data of SnO 2 (487.2 eV) [13][14][15][16], indicating that 'Sn' is present in chemical state of (+ 4). These Sn 3d 5/2 and Sn 3d 3/2 peaks are shifted to ~ 486.4 eV and ~ 494.9 eV after etching time is τ = 600 to τ = 1800 s and are shown in Fig.…”

“…Comparison with the spectrum of β-Sn metal [14], which shows the peaks of Sn 5 sp orbital states (BE ~ 7.0 eV and ~ 0 eV) suggests that the peak within the range 2-3 eV are consistent with the presence of segregated "Sn-metal" in the in our ion-sputtered (etched) Sn/SnO films [16]. The electronic states near the Dirac point are dominated by π states with major contribution coming from the out of plane p z orbital.…”