外延Ba_(0.6)Sr_(0.4)TiO_(3)铁电薄膜的制备及介电储能性能

Preparation of Epitaxial Ba_(0.6)Sr_(0.4)TiO_(3)Ferroelectric Thin Film and Its Dielectric Energy Storage Performance

利用偏轴磁控溅射技术,在(001)LaAlO_(3)单晶衬底上构架了Pt/Ba_(0.6)Sr_(0.4)TiO_(3)(BST)/La_(0.5)Sr_(0.5)CoO_(3)(LSCO)铁电电容器,研究了BST薄膜的结构与形貌、介电、漏电和储能性能。结果表明:BST薄膜为外延结构生长,表面光滑致密,其均方根粗糙度为1.228 nm。Pt/BST/LSCO电容器具有优异的介电性能,100 kHz频率下调谐率和最大损耗分别为73.73%和0.078,漏电流密度较低(106 A/cm^(2)量级)。此外,BST薄膜展现了良好的储能特性及温度稳定性,在10 kHz频率和2000 kV/cm外加场强下,其室温总储能密度、有效储能密度和储能效率分别为27.01 J/cm^(3)、16.03 J/cm^(3)和59.4%;在1200 kV/cm外加场强下,温度为105℃时储能效率可高达72.2%,这主要归因于较高温度促进了离子的热运动,从而有效提升了储能效率。

A Pt/Ba_(0.6)Sr_(0.4)TiO_(3)(BST)/La_(0.5)Sr_(0.5)CoO_(3)(LSCO)ferroelectric capacitor was fabricated on(001)LaAlO_(3)single crystal substrate using off-axis magnetron sputtering technology.The structure,morphology,and various properties,including dielectric,leakage,and energy storage performance of the BST film,were investigated in detail.The results indicate that the BST thin film is grown epitaxially and has a smooth and dense surface with a root mean square roughness of 1.228 nm.The Pt/BST/LSCO capacitor exhibits excellent dielectric properties with tunability and maximum loss of 73.73%and 0.078 at a frequency of 100 kHz,respectively,as well as lower leakage current densities(on the order of 10^(-6)A/cm^(2)).In addition,the BST thin film demonstrates favorable energy storage performance and temperature stability.At a frequency of 10 kHz and an applied electric field of 2000 kV/cm,the total energy storage density,effective energy storage density,and energy storage efficiency at room temperature are 27.01 J/cm^(3),16.03 J/cm^(3),and 59.4%,respectively.With increasing temperature up to 105℃,the energy storage efficiency can reach as high as 72.2%with an applied electric field of 1200 kV/cm,which can be attributed to the higher temperature promoting the thermal movement of ions,thereby effectively improving the energy storage efficiency.