Multilevel storage and linear optoelectronic response in mixed-dimensional photomemories.

The rapid evolution of artificial intelligence (AI) computing demands innovative memory technologies that integrate high-speed processing with energy-efficient data storage. Here, we report a mixed-dimensional photomemory device based on a CsPbBr₃/Al₂O₃/MoS₂ architecture, leveraging perovskite quantum dots (PQDs) as a photoactive floating-gate layer, a tunable Al₂O₃ dielectric, and a 2D MoS₂ channel. Optical and electrical characterization studies, including steady-state and time-resolved photoluminescence (PL), Kelvin probe force microscopy (KPFM), and current-voltage measurements, reveal the interplay of dielectric thickness and interfacial effects in governing charge transfer efficiency. By optimizing the Al₂O₃ thickness to 5.5 nm, we achieve precise control over charge transfer dynamics, enabling an optimal charge transfer rate with minimal optical energy (∼sub-pJ) to store a single positive charge in the PQDs. The device exhibits exceptional optoelectronic performance, including a nearly linear correlation between incident photon number and average photocurrent (I_ph(avg)) over two orders of magnitude, multilevel storage capability, and a memory window with a high on/off ratio. These findings establish a robust platform for next-generation perovskite-based photomemories, offering insights into energy-efficient, high-performance optoelectronic systems for advanced AI chip applications.