Tunneling devices with negative differential resistance (NDR) characteristic often suffer from bad peak-to-valley current ratios (PVR), which is due to the existence of the excess current generated by trap-assisted tunneling and phonon-assisted tunneling. How to suppress the excess current and improve PVR is a great challenge. Here, the authors propose a new strategy to suppress the excess current through cutting off the acceptable quantum states, and verify this mechanism by constructing a novel four-terminal tunneling device, which consists of the carbon nanotube as channel, Pd and Sc electrode for p-type and n-type Ohmic contact, respectively, and self-aligned split dual gates that modulate the channel to form the tunneling junction. In such a device, the window of acceptable quantum states can be cut off by increasing the sweeping rate ratio between the gate voltage to the drain voltage, so that the excess current can be suppressed. The devices exhibit significant NDR characteristics with a giant PVR of 13 500 at room temperature, and the peak current density can be up to 7 × 10⁴ A cm⁻², both of which are the highest values among all the reported low-dimensional tunneling devices.

中文翻译：

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切断碳纳米管隧道器件中可接受的量子态引起的巨大负微分电阻效应

具有负微分电阻 (NDR) 特性的隧穿器件通常会出现峰谷电流比 (PVR) 不佳的问题，这是由于陷阱辅助隧穿和声子辅助隧穿所产生的过电流的存在。如何抑制过电流并提高PVR是一个很大的挑战。在这里，作者提出了一种通过切断可接受的量子态来抑制过电流的新策略，并通过构建一种新型的四端隧穿器件来验证这一机制，该器件由碳纳米管作为通道，Pd 和 Sc 电极用于 p型和 n 型欧姆接触，以及调制沟道以形成隧道结的自对准分裂双栅极。在这样的设备中，可以通过提高栅漏电压的扫描速率比来切断可接受的量子态窗口，从而抑制过电流。该器件表现出显着的 NDR 特性，在室温下具有 13 500 的巨大 PVR，峰值电流密度可高达 7 × 10⁴  A cm ^-2，这两个值都是所有报道的低维隧道器件中的最高值。