Resonant x-ray scattering method for measuring cation stoichiometry in BaSnO3 thin films
Abstract
We develop a resonant scattering technique to measure cation stoichiometry of lanthanum-doped BaSnO3 (BSO) thin films on a DyScO3 substrate. Samples are grown by a hybrid molecular beam epitaxy method and display high room-temperature carrier mobilities. The measured thin films are grown with widely differing cation arrival rates, with Ba being evaporated from an elemental source and Sn from a SnO2 source. Differences in mobilities in these films may arise from differences in Ba/Sn cation stoichiometry. Owing to the similar scattering strength of the Ba and Sn cations, odd-order Bragg peaks of BSO are particularly sensitive to the material's cation stoichiometry, i.e., the Ba/Sn ratio. Sensitivity to cation stoichiometry is further enhanced using the technique of resonant x-ray scattering, which changes the scattering strength of a single element across the Ba L absorption edges. We determine that the Ba/Sn cation stoichiometry varies from unity by less than 1% for films of mobility ranging from 84.8 to 144 cm2/(V s) and conclude that the mobility of these films scales with film thickness and growth rate rather than stoichiometry.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Dec 22, 2021
- Source ID
- 10.1116/6.0001454
Entities
People
- Charles Ahn
- Claudia Lau
- Evguenia Karapetrova
- Frederick J. Walker
- Juan Jiang
- Nicholas G. Combs
- Susanne Stemmer
Organizations
- Argonne National Laboratory
- Office of Naval Research
- United States Department of Energy
- University of California
- Yale University