Ultrafast‐Programmable 2D Homojunctions Based on van der Waals Heterostructures on a Silicon Substrate

Abstract The development of electrically ultrafast‐programmable semiconductor homojunctions can lead to transformative multifunctional electronic devices. However, silicon‐based homojunctions are not programmable so that alternative materials need to be explored. Here 2D, multi‐functional, lateral homojunctions made of van der Waals heterostructures with a semi‐floating‐gate configuration on a p⁺⁺ Si substrate feature atomically sharp interfaces and can be electrostatically programmed in nanoseconds, more than seven orders of magnitude faster than other 2D‐based homojunctions. By applying voltage pulses with different polarities, lateral p−n, n⁺−n and other types of homojunctions can be formed, varied, and reversed. The p−n homojunctions possess a high rectification ratio of up to ≈10⁵ and can be dynamically switched between four distinct conduction states with the current spanning over nine orders of magnitude, enabling them to function as logic rectifiers, memories, and multi‐valued logic inverters. Built on a p⁺⁺ Si substrate, which acts as the control gate, the devices are compatible with Si technology.