Effect of donor and acceptor dopants on Schottky barrier heights and vacancy concentrations in barium strontium titanate

This paper discusses the effect of donors and acceptors on the electronic band structure and defect properties of Ba0.7Sr0.3TiO3 film (BST). Based on X-Ray Photoelectron Spectroscopy (XPS) data and an extension of previous work by Robertson and Chen (Robertson, J. and Chen, C. W., Schottky barrier heights of tantalum oxide, barium strontium titanate, lead titanate, and strontium bismuth tantalate. Appl. Phys. Lett., 1999, 74, 1168-1170), Schottky barrier heights are calculated for BST films in which La and Mn dopants have been added (0.7%). The barrier height expression of Cowley and Sze (Cowley, A. M. and Sze, S. M., Journal of Applied Physics, 1965, 36, 3212) is discussed with attention to the term neglected in their original paper. The effect of dopants on the oxygen vacancy concentration is also discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.