Issue 21, 2012

Epitaxial TiO2/SnO2 core–shell heterostructure by atomic layer deposition

Abstract

Taking TiO2/SnO2 core–shell nanowires (NWs) as a model system, we systematically investigate the structure and the morphological evolution of this heterostructure synthesized by atomic layer deposition/epitaxy (ALD/ALE). All characterizations, by X-ray diffraction, high-resolution transmission electron microscopy, selected area electron diffraction and Raman spectra, reveal that single crystalline rutile TiO2 shells can be epitaxially grown on SnO2 NWs with an atomically sharp interface at low temperature (250 °C). The growth behavior of the TiO2 shells highly depends on the surface orientations and the geometrical shape of the core SnO2 NW cross-section. Atomically smooth surfaces are found for growth on the {110} surface. Rough surfaces develop on {100} surfaces due to (100) − (1 × 3) reconstruction, by introducing steps in the [010] direction as a continuation of {110} facets. Lattice mismatch induces superlattice structures in the TiO2 shell and misfit dislocations along the interface. Conformal epitaxial growth has been observed for SnO2 NW cores with an octagonal cross-section ({100} and {110} surfaces). However, for a rectangular core ({10[1 with combining macron]} and {010} surfaces), the shell also derives an octagonal shape from the epitaxial growth, which was explained by a proposed model based on ALD kinetics. The surface steps and defects induced by the lattice mismatch likely lead to improved photoluminescence (PL) performance for the yellow emission. Compared to the pure SnO2 NWs, the PL spectrum of the core–shell nanostructures exhibits a stronger emission peak, which suggests potential applications in optoelectronics.

Graphical abstract: Epitaxial TiO2/SnO2 core–shell heterostructure by atomic layer deposition

Article information

Article type
Paper
Submitted
05 Feb 2012
Accepted
21 Mar 2012
First published
27 Mar 2012

J. Mater. Chem., 2012,22, 10665-10671

Epitaxial TiO2/SnO2 core–shell heterostructure by atomic layer deposition

A. Nie, J. Liu, Q. Li, Y. Cheng, C. Dong, W. Zhou, P. Wang, Q. Wang, Y. Yang, Y. Zhu, Y. Zeng and H. Wang, J. Mater. Chem., 2012, 22, 10665 DOI: 10.1039/C2JM30690E

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Spotlight

Advertisements