Programmable transition metal dichalcogenide homojunctions controlled by nonvolatile ferroelectric domains

Semiconductor devices based on two-dimensional (2D) transition metal dichalcogenides could help overcome the scaling limits of silicon complementary metal–oxide–semiconductor (CMOS) technology. However, the development of atomically thin devices requires approaches to control the carrier type in 2D semiconductors. Here, we show that a scanning probe can be used to control the polarization of ferroelectric polymers deposited on 2D transition metal dichalcogenides in order to define carrier injection and achieve p-type and n-type doping. The approach allows lateral p–n, n–p, n–n and p–p homojunctions to be arbitrarily formed and altered. Molybdenum ditelluride (MoTe₂) p–n homojunction devices constructed using this method exhibit high current rectification ratios of 10³ and good optoelectronic properties (responsivity of 1.5 A W⁻¹). Unconventional nonvolatile memory devices are also built, such as an electrical writing and optical reading memory device, without the restrictions of physical source, drain or gate electrodes, and a quasi-nonvolatile memory with a refresh time of 100 s and a write/erase speed of 10 µs.