Monolayer hydrophilic MoS2 with strong charge trapping for atomically thin neuromorphic vision systems

Abstract

Effective control of electrical and optoelectronic properties of two-dimensional layered materials, one of the key requirements for applications in advanced optoelectronics with multiple functions, has been hindered by the difficulty of elemental doping, which is commonly utilized in Si technology. In this study, we proposed a new method to synthesize hydrophilic MoS₂ monolayers through covalently introducing hydroxyl groups during their growth process. These hydroxyl groups exhibit a strong capability of charge trapping, and thus the hydrophilic MoS₂ monolayers achieve excellent electrical, optical, and memory properties. Optical memory transistors, made from a single component of monolayer hydrophilic MoS₂, exhibit not only excellent light-dependent and time-dependent photoelectric performance, but also good photo-responsive memory characteristics with over multi-bit storage and more than 10⁴ switching ratios. Atomically thin neuromorphic vision systems (with a concept of proof of 10 × 10 neuromorphic visual image) are manufactured from arrays of hydrophilic MoS₂ optical memory transistors, showing high quality image sensing and memory functions with a high color resolution. These results proved our new concepts to realize image memorization and simplify the pixel matrix preparation process, which is a significant step toward the development of future artificial visual systems.