Nd掺杂HfO_(2)薄膜的分子束外延制备及铁电性  

Ferroelectricity in Nd Doped HfO_(2) Films Grown by Molecular Beam Epitaxy

作　　者：刘育玮 矫佩杰 茆伟 杨江枫 郑宁冲 王鹏 吴迪 聂越峰 LIU Yuwei;JIAO Peijie;MAO Wei;YANG Jiangfeng;ZHENG Ningchong;WANG Peng;WU Di;NIE Yuefeng(Jiangsu Key Laboratory of Artificial Functional Materials,National Laboratory of Solid State Microstructures,College of Engineering and Applied Sciences,Nanjing University,Nanjing 210093,China;Department of Physics,Univesity of Warwick,Coventry CV47AL,UK)

机构地区：[1]南京大学现代工程与应用科学学院,固体微结构物理国家重点实验室,江苏省功能材料设计原理与应用技术重点实验室,南京210093 [2]华威大学物理系,英国考文垂CV47AL

出　　处：《硅酸盐学报》2023年第12期3039-3045,共7页Journal of The Chinese Ceramic Society

基　　金：国家重点研发计划(2022YFA1402502,2021YFA1400400);国家自然科学基金(52232001)。

摘　　要：掺杂Hf O_(2)铁电薄膜在非易失性存储器件中的重要应用前景使其成为当前凝聚态物理与材料科学领域的一个研究热点。近年来,结果表明:La掺杂Hf O_(2)拥有优异的铁电性能,铁电剩余极化强度为45μC/cm~2,是目前Hf O_(2)基薄膜材料中报道的最高值。由于Nd与La的化学性质相近,Nd掺杂同样有望增强HfO_(2)的铁电性,但相关研究工作却鲜有报道。使用氧化物分子束外延技术,在La_(0.67)Sr_(0.33)Mn O_(3)(底电极)/SrTiO_(3)(001)衬底上外延生长高质量Nd掺杂Hf O_(2)(Nd:HfO_(2))薄膜。X射线衍射以及高分辨电镜表征结果均显示Nd掺杂有助于诱导Hf O_(2)从单斜相向正交相的转变,压电力显微镜和铁电测试仪进一步证实正交相Nd:Hf O_(2)具有良好的铁电性。此外,高分辨电子显微镜表征还发现Nd:Hf O_(2)靠近界面处存在四方相结构,衔接(111)晶向的Nd:Hf O_(2)和(001)晶向的钙钛矿氧化物衬底。Nd:Hf O_(2)薄膜的外延生长和铁电性的系统研究,扩充了掺杂Hf O_(2)的研究体系。The application of doped HfO_(2) ferroelectric thin films in nonvolatile memory devices becomes popular in condensed matter physics and materials science.Recent studies indicate that La doped HfO_(2) has excellent ferroelectric properties,and the ferroelectric remanent polarization is 45μC/cm~2 as the maximum value reported.Nd doping is expected to enhance the ferroelectric properties of HfO_(2) due to its similar chemical properties of Nd and La,but little research has been reported.In this paper,high quality Nd-doped HfO_(2) (i.e.,Nd:HfO_2) thin films were grown on La_(0.67)Sr_(0.33)MnO_(3) (bottom electrode)/SrTiO_(3) (001)substrates by using oxide molecular beam epitaxy.According to the results by X-ray diffraction and high-resolution electron microscopy,Nd doping can induce the transition of HfO_(2) from a monoclinic phase to an orthorhombic phase.In addition,the results by high resolution electron microscopy also show that Nd:HfO_(2) has a tetragonal phase structure near the interface,connecting (111) crystalline Nd:HfO_(2) and (001) crystalline perovskite oxide substrates.The systematic studies on epitaxial growth and ferroelectric properties of Nd:HfO_(2) films can expand the research of doped HfO_2.

关 键 词：氧化铪 铁电 分子束外延 掺杂 

分 类 号：O484.1[理学—固体物理]