Negative differential resistance (NDR) in NbO_x films attracts attention for potential application in neuromorphic computing. A continuous S‐type and abrupt snapback NDR characteristics are reported for NbO_x devices. The NDR characteristics are expected to depend on the nature of the switching path in NbO_x. Previous NDR studies have been performed mainly on amorphous NbO_x films with an electroforming process to create a switching path. Herein, the NDR characteristics of a forming‐free NbO_x device with crystalline NbO₂ phases are investigated and these are compared with those of an amorphous NbO_x device with forming. The forming‐free NbO_x device exhibits a secondary abrupt snapback NDR in addition to the initial S‐type NDR, possibly due to a metal–insulator transition in the NbO₂ phases. Meanwhile, the amorphous NbO_x devices only show a continuous S‐type behavior.

中文翻译：

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结晶NbO2相的无成形NbOx的负微分电阻特性

NbO _x薄膜中的负微分电阻（NDR）吸引了人们的注意，有望在神经形态计算中得到应用。据报告，NbO _x设备具有连续的S型和突然的NDR突然恢复特性。预期NDR特性取决于NbO _x中切换路径的性质。以前的NDR研究主要是在非晶NbO _x薄膜上进行的，该薄膜采用电铸工艺来形成开关路径。在此，研究了具有结晶NbO ₂相的无成形NbO _x器件的NDR特性，并将其与具有成形性的非晶NbO _x器件的NDR特性进行了比较。无成型NbO _x除了最初的S型NDR之外，该设备还具有二次突然的骤回NDR，这可能是由于NbO ₂相中的金属-绝缘体跃迁所致。同时，非晶NbO _x器件仅表现出连续的S型行为。