High‐Speed Flexible Schottky Diodes Based on Carbon Nanotubes

ABSTRACT The rapid advancements in fifth and sixth‐generation (5 and 6G) mobile communication networks, along with the growing demands of the Internet of Things (IoT), necessitate the development of high‐speed diodes on flexible substrates. However, most of the flexible diodes with low operating frequencies are limited by relatively low material mobility, large resistance, and capacitance. In this work, we present a flexible Schottky diode (FSBD) based on high‐purity semiconducting carbon nanotube (CNT) network films, offering an innovative solution to the long‐standing challenge of achieving large‐area, cost‐effective, high‐performance radio frequency (RF) diodes on flexible substrates. Using polyimide (PI) as the substrate and a low‐temperature‐compatible fabrication process, the CNT‐based flexible Schottky diodes (CNT‐FSBDs) exhibit a remarkable responsivity of 6 A/W, an intrinsic cut‐off frequency of 153 GHz, and an extrinsic cut‐off frequency exceeding 10 GHz at zero bias. Furthermore, the diodes achieve efficient response at low input RF power levels (−25 dBm), owing to the low resistance, zero‐bias operation, and high responsivity. These features underpin the FSBDs performance in flexible, high‐efficiency rectification applications. Additionally, the CNT‐FSBDs exhibit excellent uniformity and stability, making them ideal for scalable manufacturing in wearable devices, large‐area sensing systems, wireless energy harvesting, and next‐generation communication technologies.