Pushing the detection of cation nonstoichiometry to the limit
Name
PhysRevMaterials.3.043802.pdf
Description
Published version
Size
1.61 MB
Format
Adobe PDF
Checksum (MD5)
0349cc006f4e20dfb97a5dae86956ecc
Author(s)
Lu, Qiyang
Yildiz, Bilge
Date Issued
April 2019
Journal
Physical review materials
Publisher
American Physical Society (APS)
Citation
Riva, Michele, et al., "Pushing the detection of cation nonstoichiometry to the limit." Physical review materials 3 (2019): no. 043802 doi: 10.1103/PhysRevMaterials.3.043802 ©2019 Author(s)
Version
Final published version
Abstract
Nanoscale complex-oxide thin films prepared by well-established growth techniques, such as pulsed-laser deposition or molecular-beam epitaxy, often exhibit compositions that deviate from the ideal stoichiometry. Even small variations in composition can lead to substantial changes in the technologically relevant electronic, magnetic, and optical properties of these materials. To assess the reasons behind this variability, and ultimately to allow tuning the properties of oxide films with precise control of the deposition parameters, high-resolution detection of the nonstoichiometry introduced during growth is needed. The resolution of current techniques, such as x-ray diffraction, fluorescence, or spectroscopy, is limited to estimating composition differences in the percent level, which is often insufficient for electronic-device quality. We develop an unconventional approach based on scanning tunneling microscopy for enabling the determination of cation imbalance introduced in thin films with exceptionally small detection limit. We take advantage of the well-controlled surface reconstructions on SrTiO3(110), and use the established relation between those reconstructions and the surface composition to assess the cation excess deposited in pulsed-laser grown SrTiO3(110) films. We demonstrate that a <0.1% change in cation nonstoichiometry is detectable by our approach. Furthermore, we show that, for thin films that accommodate all the nonstoichiometry at the surface, this method has no fundamental detection limit.
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Massachusetts Institute of Technology. Laboratory for Electrochemical Interfaces
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Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1103/PHYSREVMATERIALS.3.043802
