In this study, a solution-processed bilayer structure ZrO₂/SnO₂ resistive switching (RS) random access memory (RRAM) is presented for the first time. The precursors of SnO₂ and ZrO₂ are Tin(Ⅱ) acetylacetonate (Sn(AcAc)₂) and zirconium acetylacetonate (Zr(C₅H₇O₂)₄), respectively. The top electrode was deposited with Ti using an E-beam evaporator, and the bottom electrode used an indium–tin–oxide glass wafer. We created three devices: SnO₂ single-layer, ZrO₂ single-layer, and ZrO₂/SnO₂ bilayer devices, to compare RS characteristics such as the I–V curve and endurance properties. The SnO₂ and ZrO₂ single-layer devices showed on/off ratios of approximately 2 and 51, respectively, along with endurance switching cycles exceeding 50 and 100 DC cycles. The bilayer device attained stable RS characteristics over 120 DC endurance switching cycles and increased on/off ratio ∼2.97 × 10². Additionally, the ZrO₂/SnO₂ bilayer bipolar switching mechanism was explained by considering the Gibbs free energy (ΔG ^o) difference in the ZrO₂ and SnO₂ layers, where the formation and rupture of conductive filaments were caused by oxygen vacancies. The disparity in the concentration of oxygen vacancies, as indicated by the Gibbs free energy difference between ZrO₂ (ΔG ^o = −1100 kJ mol⁻¹) and SnO₂ (ΔG ^o = −842.91 kJ mol⁻¹) implied that ZrO₂ exhibited a higher abundance of oxygen vacancies compared to SnO₂, resulting in improved endurance and on/off ratio. X-ray photoelectron spectroscopy analyzed oxygen vacancies in ZrO₂ and SnO₂ thin films. The resistance switching characteristics were improved due to the bilayer structure, which combines a higher oxygen vacancy concentration in one layer with a lower oxygen vacancy concentration in the switching layer. This configuration reduces the escape of oxygen vacancies to the electrode during RS.

中文翻译：

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通过氧空位差改进溶液处理的 ZrO2/SnO2 双层 RRAM 的电阻开关特性

在这项研究中，首次提出了一种溶液处理的双层结构ZrO ₂ /SnO _{2电阻开关（RS）随机存取存储器（RRAM）。 SnO 2}和ZrO ₂的前体分别是乙酰丙酮锡(Ⅱ)(Sn(AcAc) ₂ )和乙酰丙酮锆(Zr(C ₅ H ₇ O ₂ ) ₄ )。顶部电极使用电子束蒸发器沉积钛，底部电极使用氧化铟锡玻璃晶片。我们创建了三种器件：SnO ₂单层、ZrO ₂单层和ZrO ₂ /SnO ₂双层器件，以比较RS特性，例如我–V曲线和耐力特性。 SnO ₂和ZrO ₂单层器件的开/关比分别约为2和51，并且耐久开关周期超过50和100个直流周期。该双层器件在超过 120 个直流耐久开关周期内获得了稳定的 RS 特性，并且开/关比提高到~2.97 × 10 ²。_此外，通过考虑吉布斯自由能( _ΔG ^o）ZrO ₂和SnO ₂层的差异，其中导电丝的形成和断裂是由氧空位引起的。氧空位浓度的差异，如 ZrO ₂之间的吉布斯自由能差所示(ΔG ^o = -1100 kJ mol ^-1 ) 和 SnO ₂ (ΔG ^o = -842.91 kJ mol ^-1）表明，与 SnO _{2相比，ZrO 2}表现出更高丰度的氧空位，从而提高了耐久性和开/关比。 X射线光电子能谱分析了ZrO ₂和SnO ₂薄膜中的氧空位。由于双层结构将一层中较高的氧空位浓度与开关层中较低的氧空位浓度相结合，电阻切换特性得到了改善。这种配置减少了 RS 期间氧空位逃逸到电极的情况。