Effect of thickness-dependent crystal mosaicity and chemical defect on electric properties in yttrium-stabilized epitaxial HfO2 thin films

Abstract

Epitaxial pseudo cubic yttrium-stabilized Y0.05Hf0.95O2 (YHO) thin films with bottom electrode layers of Pr0.5Sr0.5CoO3 were deposited on (001)-oriented LaAlO3 (LAO) substrates by using the pulsed laser deposition system. The crystal structure and thickness of the films were confirmed by θ–2θ scan and X-ray reflectivity via X-ray diffraction technology, respectively. Reciprocal space mapping (RSM) was performed to clarify the microstructure of the epitaxial YHO films affected by LAO substrates, and the result of symmetric RSMs revealed that the crystal mosaicity of the YHO films increases with the increasing film thicknesses. Moreover, the dominant conduction mechanisms of all the YHO films were ohmic conduction in the low electric field. At a high applied electric field, the YHO-5.4 nm film was determined by the space-charge-limited current behavior, while the samples of the YHO-9.8 nm and YHO-19.2 nm films were determined by ohmic conduction. The temperature-dependent I–V characteristics of the YHO films with different thicknesses have been also obtained, revealing that the current of all the YHO films generally increases with the increase in temperature, which attributed to the crystal mosaicity and chemical defects.

Highly Stable In-Plane Microwave Magnetism in Flexible Li0.35Zn0.3Fe2.35O4(111) Epitaxial Thin Films for Wearable Devices

“…It is clear that the LZFO sample shows excellent interference patterns, demonstrating a good smooth surface. In the meantime, the growth rate and thickness of the LZFO thin film can be described by Parratt’s formula Figure e shows the atomic force microscopy (AFM) image of the surface of the LZFO sample, and its corresponding line profile is shown in Figure f.…”

“…In the meantime, the growth rate and thickness of the LZFO thin film can be described by Parratt's formula. 21 Figure 1e shows the atomic force microscopy (AFM) image of the surface of the LZFO sample, and its corresponding line profile is shown in Figure 1f. The AFM image further proves that the LZFO sample has a smooth surface.…”

Domain orientation relationship of orthorhombic and coexisting monoclinic phases of YO1.5-doped HfO2 epitaxial thin films

“…19) YHO epitaxial films prepared using various factors, such as the orientation and type of substrate, have also been reported. [20][21][22][23] However, their domain structure is rather different from those of conventional perovskite-type ferroelectric thin films such as PbTiO 3 and the structure has not been well understood in detail. 24,25) The polar orthorhombic phase of YHO thin films is ferroelectric and ferroelastic, such that there are 180°-type and non-180°-type domain structures.…”