Carbon Nanotube Diodes Operating at Frequencies of Over 50 GHz

Abstract Radiofrequency (RF) diodes used for fifth and sixth‐generation (5G and 6G) mobile and wireless communication networks generally require ultrahigh cut‐off frequencies and high integration densities of devices with different functions on a single chip and at low cost. Carbon nanotube diodes are promising devices for radiofrequency applications, but the cut‐off frequencies are still far below the theoretical estimates. Here, a carbon nanotube diode that operates in the millimeter‐wave frequency bands and is based on solution‐processed, high‐purity carbon nanotube network films is reported. The carbon nanotube diodes exhibit an intrinsic cut‐off frequency over 100 GHz and the as‐measured bandwidth can exceed 50 GHz at least. Furthermore, The rectification ratio of the carbon nanotube diode by approximately three times by using yttrium oxide for local p‐type doping in the diode channel is improved.