Publication Date:
2016-07-26
Description:
The synthesis of a 50 unit cell thick n = 4 Sr n+1 Ti n O 3n+1 (Sr 5 Ti 4 O 13 ) Ruddlesden-Popper (RP) phase film is demonstrated by sequentially depositing SrO and TiO 2 layers in an alternating fashion using hybrid molecular beam epitaxy (MBE), where Ti was supplied using titanium tetraisopropoxide (TTIP). A detailed calibration procedure is outlined for determining the shuttering times to deposit SrO and TiO 2 layers with precise monolayer doses using in-situ reflection high energy electron diffraction (RHEED) as feedback. Using optimized Sr and TTIP shuttering times, a fully automated growth of the n = 4 RP phase was carried out over a period of 〉4.5 h. Very stable RHEED intensity oscillations were observed over the entire growth period. The structural characterization by X-ray diffraction and high resolution transmission electron microscopy revealed that a constant periodicity of four SrTiO 3 perovskite unit cell blocks separating the double SrO rocksalt layer was maintained throughout the entire film thickness with a very little amount of planar faults oriented perpendicular to the growth front direction. These results illustrate that hybrid MBE is capable of layer-by-layer growth with atomic level precision and excellent flux stability.
Print ISSN:
0003-6951
Electronic ISSN:
1077-3118
Topics:
Physics
