Rodriguez-Fano Michael, Haydoura Mohamad, Tranchant Julien, Janod Etienne, Corraze Benoît, Jouan Pierre-Yves, Cario Laurent, Besland Marie-Paule
Institut des Matériaux Jean Rouxel, IMN, Université de Nantes, CNRS, F-44000 Nantes, France.
ACS Appl Mater Interfaces. 2023 Nov 29;15(47):54611-54621. doi: 10.1021/acsami.3c09387. Epub 2023 Nov 14.
Memories based on the insulator-to-metal transition in correlated insulators are promising to overcome the limitations of alternative nonvolatile memory technologies. However, associated performances have been demonstrated so far only on narrow-gap compounds, such as (VCr)O, exhibiting a tight memory window. In the present study, V-substituted CrO compounds (CrV)O have been synthesized and widely investigated in thin films, single crystals, and polycrystalline powders, for the whole range of chemical composition (0 < < 1). Physicochemical, structural, and optical properties of the annealed magnetron-sputtered thin films are in very good agreement with those of polycrystalline powders. Indeed, all compounds exhibit the same crystalline structure with a cell parameter evolution consistent with a solid solution over the whole range of values, as demonstrated by X-ray diffraction and Raman scattering. Moreover, the optical band gap of V-substituted CrO compounds decreases from 3 eV for CrO to 0 eV for VO. In the same way, resistivity is decreased by almost 5 orders of magnitude as the V content is varying from 0 to 1, similarly in thin films and single crystals. Finally, a reversible resistive switching has been observed for thin films of three selected V contents ( = 0.30, 0.70, and 0.95). Resistive switching performed on MIM devices based on a 50 nm thick (CrV)O thin film shows a high endurance of 1000 resistive switching cycles and a memory window / higher by 3 orders of magnitude, as compared to (CrV)O. This comprehensive study demonstrates that a large range of memory windows can be reached by tuning the band gap while varying the V content in the (CrV)O solid solution. It thus confirms the potential of correlated insulators for memory applications.
基于关联绝缘体中绝缘体 - 金属转变的存储器有望克服替代非易失性存储技术的局限性。然而，到目前为止，相关性能仅在窄带隙化合物（如(VCr)O）上得到了证明，其呈现出狭窄的存储窗口。在本研究中，已合成了V取代的CrO化合物（CrV）O，并在薄膜、单晶和多晶粉末中对其整个化学成分范围（0 < < 1）进行了广泛研究。退火后的磁控溅射薄膜的物理化学、结构和光学性质与多晶粉末的性质非常吻合。实际上，所有化合物都表现出相同的晶体结构，其晶胞参数演变与整个 值范围内的固溶体一致，这通过X射线衍射和拉曼散射得到了证明。此外，V取代的CrO化合物的光学带隙从CrO的3 eV降至VO的0 eV。同样，当V含量 从0变化到1时，电阻率降低了近5个数量级，在薄膜和单晶中情况类似。最后，对于三种选定V含量（ = 0.30、0.70和0.95）的薄膜，观察到了可逆电阻开关。基于50 nm厚的(CrV)O薄膜在MIM器件上进行的电阻开关显示出1000次电阻开关循环的高耐久性，并且与(CrV)O相比，存储窗口 / 高3个数量级。这项全面的研究表明，通过调节带隙并改变(CrV)O固溶体中的V含量，可以实现大范围的存储窗口。因此，它证实了关联绝缘体在存储器应用中的潜力。
