Valence-band density of states and surface electron accumulation in epitaxial SnO<sub>2</sub> films



Farahani, SK Vasheghani, Veal, TD ORCID: 0000-0002-0610-5626, Mudd, JJ, Scanlon, DO, Watson, GW, Bierwagen, O, White, ME, Speck, JS and McConville, CF
(2014) Valence-band density of states and surface electron accumulation in epitaxial SnO<sub>2</sub> films. PHYSICAL REVIEW B, 90 (15).

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Abstract

The surface band bending and electronic properties of SnO2(101) films grown on r-sapphire by plasma-assisted molecular beam epitaxy have been studied by Fourier-transform infrared spectroscopy (FTIR), x-ray photoemission spectroscopy (XPS), Hall effect, and electrochemical capacitance-voltage measurements. The XPS results were correlated with density functional theory calculation of the partial density of states in the valence-band and semicore levels. Good agreement was found between theory and experiment with a small offset of the Sn 4d levels. Homogeneous Sb-doped SnO2 films allowed for the calculation of the bulk Fermi level with respect to the conduction-band minimum within the k·p carrier statistics model. The band bending and carrier concentration as a function of depth were obtained from the capacitance-voltage characteristics and model space charge calculations of the Mott-Schottky plots at the surface of Sb-doped SnO2 films. It was quantitatively demonstrated that SnO2 films have downward band bending and surface electron accumulation. The surface band bending, unoccupied donor surface-state density, and width of the accumulation region all decrease with increasing Sb concentration.

Item Type: Article
Depositing User: Symplectic Admin
Date Deposited: 20 Mar 2015 16:20
Last Modified: 05 Oct 2023 11:35
DOI: 10.1103/PhysRevB.90.155413
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/2008432