Barriuso Eduardo, Koutsogiannis Panagiotis, Serrate David, Herrero-Martín Javier, Jiménez Ricardo, Magén César, Algueró Miguel, Algarabel Pedro A, Pardo José A
Instituto de Nanociencia y Materiales de Aragón, Universidad de Zaragoza-CSIC, 50018 Zaragoza, Spain.
Laboratorio de Microscopías Avanzadas, Universidad de Zaragoza, 50018 Zaragoza, Spain.
Nanomaterials (Basel). 2022 Apr 6;12(7):1232. doi: 10.3390/nano12071232.
Single-phase epitaxial HfZrO films with non-centrosymmetric orthorhombic structure have been grown directly on electrode-free corundum (α-AlO) substrates by pulsed laser deposition. A combination of high-resolution X-ray diffraction and X-ray absorption spectroscopy confirms the epitaxial growth of high-quality films belonging to the 2 space group, with [111] out-of-plane orientation. The surface of a 7-nm-thick sample exhibits an atomic step-terrace structure with a corrugation of the order of one atomic layer, as proved by atomic force microscopy. Scanning transmission electron microscopy reveals that it consists of grains with around 10 nm lateral size. The polar nature of this film has been corroborated by pyroelectric measurements. These results shed light on the mechanisms of the epitaxial stabilization of the ferroelectric phase of hafnia.
具有非中心对称正交结构的单相外延HfZrO薄膜已通过脉冲激光沉积直接生长在无电极刚玉（α-Al₂O₃）衬底上。高分辨率X射线衍射和X射线吸收光谱的结合证实了属于2空间群的高质量薄膜的外延生长，其具有[111]面外取向。原子力显微镜证明，一个7纳米厚样品的表面呈现出原子台阶-平台结构，其起伏约为一个原子层的量级。扫描透射电子显微镜显示，它由横向尺寸约为10纳米的晶粒组成。热释电测量证实了该薄膜的极性。这些结果为氧化铪铁电相外延稳定的机制提供了线索。
