A Light‐Programmed Rewritable Lattice‐Mediated Multistate Memory for High‐Density Data Storage

Mainstream non‐volatile memory (NVM) devices based on floating gate structures or phase‐change/ferroelectric materials face inherent limitations that compromise their suitability for long‐term data storage. To address this challenge, a novel memory device based on light‐programmed lattice engineering of thin rhenium disulfide (ReS 2 ) flakes is proposed. By inducing sulfur vacancies in the ReS 2 channel through light illumination, the device's electrical conductivity is modified accordingly and multiple conductance states for data storage therefore are generated. The device exhibits more than 128 distinct states with linearly increasing conductance, corresponding to a sevenfold increase in storage density. Through further optimization to achieve atomic‐level precision in defect creation, it is possible to achieve even higher storage densities. These states are extremely stable in vacuum or inert ambient showing long retention of >10 years, while they can be erased upon exposure to the air. The ReS 2 memory device can maintain its stability over multiple program‐erase operation cycles and shows superior wavelength discrimination capability for incident light in the range of 405–785 nm. This device represents a significant contribution to NVM technology by offering the ability to store information in multistate memory and enabling filter‐free color image recorder applications.