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 PtTe2-x films via composition engineering strategies. Wafer-scale PtTe2-x films are grown by co-sputtering, exhibiting a tunable bipolar photoresponse by controlling the coexistence of metallic Pt and layered PtTe2 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.
Zhang et al. (Fri,) studied this question.