Composition-Engineered PtTe _2-x Films for Monolithic Integration of Photosensing, Memory, and Computing Based on Bipolar Photoresponse

Optoelectronic synapses with a bidirectional photoresponse serve as a highly promising platform, enabling a highly integrated sensing, storage, and computing architecture. However, most existing devices rely on complex heterojunction architectures that require multilayer fabrication and high-temperature processing, severely limiting scalability and monolithic integration. In this work, we present multifunctional synaptic devices based on PtTe 2-x films via composition engineering strategies. Wafer-scale PtTe 2-x films are grown by co-sputtering, exhibiting a tunable bipolar photoresponse by controlling the coexistence of metallic Pt and layered PtTe 2 phases. This unique photoresponse behavior originates from the intrinsic competition between bolometric and photoconductive mechanisms, allowing reversible photocurrent polarity modulation across a broad spectral range (405−1550 nm). Besides, robust excitatory and inhibitory synaptic plasticity is demonstrated in the optimized device. Furthermore, 8 × 8 synaptic arrays were fabricated to emulate visual perception and memory functions. Notably, five reconfigurable logic operations of the AND, OR, NOT, NOR, and NAND are implemented within a single device leveraging the bipolar photoresponse. This work not only offers deep understanding of the competition and modulation of photophysical mechanisms, but also provides an effective strategy for developing next-generation artificial visual systems.