Abstract
The morphology and microstructure of BaTiO3/SrTiO3 (BTO/STO) superlattices grown epitaxially on STO (001) substrates by a computer-controlled laser molecular-beam epitaxy deposition system have been characterized by means of atomic force microscopy and high-resolution transmission electron microscopy (HRTEM). It is found that the HRTEM images taken along the [120] direction of BTO and STO show the maximal contrast difference. It is, therefore, observed that the superlattices consist of a highly oriented and single-crystalline multilayered structure. As identified by HRTEM, the number of unit cells in each BTO or STO layer matches very well with that obtained from reflection high-energy electron diffraction oscillations. The surfaces and interfaces of the superlattices are atomically smooth. In the superlattices, the ratio between the c axis of BTO and STO is about 4% larger than that measured from BTO or STO bulk crystals.
Published Version
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