Atomically thin materials can be used to build novel forms of conventional semiconductor heterostructure devices. One such device is a resonant tunnelling diode, which can exhibit negative differential resistance and usually consists of a quantum-well structure between two barrier layers. Here, we show that a twisted black phosphorus homostructure can be used to create a resonant tunnelling diode. The devices have a trilayer structure in which a thin non-degenerate black phosphorus layer is sandwiched between two thicker degenerate black phosphorus layers. The interlayer coupling strength depends sensitively on the twist angle between the layers, and thus the twist angle can be used to control the vertical transport behaviour, from ohmic to tunnelling. Because resonant tunnelling through quantum-well states occurs without the need for a physical tunnelling barrier, our devices exhibit a higher tunnelling conductance and negative differential resistance peak-to-valley current ratio than resonant tunnelling diodes based on van der Waals heterostructures.

原子级薄材料可用于构建新形式的传统半导体异质结构器件。一种这样的器件是谐振隧道二极管，它可以表现出负差分电阻，通常由两个势垒层之间的量子阱结构组成。在这里，我们展示了扭曲的黑磷同质结构可用于创建谐振隧道二极管。该器件具有三层结构，其中薄的非简并黑磷层夹在两个较厚的简并黑磷层之间。层间耦合强度敏感地取决于层之间的扭转角，因此扭转角可用于控制从欧姆到隧道的垂直传输行为。