Atomic mapping of Ruddlesden-Popper faults in transparent conducting BaSnO3-based thin films.

W Y Wang,Y L Zhu,S-W Cheong,Y B Xu,Y Liu,X L Ma,B Gao,Y L Tang,J Suriyaprakash

doi:10.1038/srep16097

Abstract

Doped BaSnO3 has arisen many interests recently as one of the promising transparent conducting oxides for future applications. Understanding the microstructural characteristics are crucial for the exploration of relevant devices. In this paper, we investigated the microstructural features of 0.001% La doped BaSnO3 thin film using both conventional and aberration corrected transmission electron microscopes. Contrast analysis shows high densities of Ruddlesden-Popper faults in the film, which are on {100} planes with translational displacements of 1/2a < 111 > . Atomic EELS element mappings reveal that the Ruddlesden-Popper faults are Ba-O layer terminated, and two kinds of kink structures at the Ruddlesden-Popper faults with different element distributions are also demonstrated. Quantitative analysis on lattice distortions of the Ruddlesden-Popper faults illustrates that the local lattice spacing poses a huge increment of 36%, indicating that large strains exist around the Ruddlesden-Popper faults in the film.

Highlights

Owing to the high electrical conductivity and optical transparent properties, transparent conducting oxides (TCOs) have received extensive attentions and demands for a large number of applications, such as optical electrode in solar cells, flat-panel displays, and sensors etc[1,2,3]
Lattice mismatch is released by generating misfit dislocations (MDs) at or near the interfaces[19,20,21,22], and the formation of the MDs is often related to evolution of threading dislocations (TDs)[23]
It is expected that there are a large number of MDs and TDs in the BSO/LSO/STO thin film due to the misfit strain relaxation

Summary

Introduction

Owing to the high electrical conductivity and optical transparent properties, transparent conducting oxides (TCOs) have received extensive attentions and demands for a large number of applications, such as optical electrode in solar cells, flat-panel displays, and sensors etc[1,2,3]. Misfit dislocations (MDs) are commonly observed in thin films while one dimensional electron chains are found at these MDs in magnetic thin films[11] Interfaces, such as film/substrate interfaces, twins or stacking faults, can provide another degree of freedom to mediate the property of thin films, where superconductivity[13], ferroelectricity[14], and novel magnetic phase[15] can be generated. At these interfaces, both the ionic potential and electronic state are distinct from those of the bulk matrix and account for the superior properties[12]. The element distributions and lattice distortions around the RP faults are explored

Methods

Results

Conclusion