Prolonged Photocarrier Lifetime of Pt-Embedded VO2 Thin Films for Photonic Reservoir Computing

Abstract

Overcoming the trade-off between strong photoresponse and fading memory remains a key challenge for efficient photonic reservoir computing based on photoactive materials. In this work, we demonstrate that Pt nanoparticle-embedded VO₂ devices can simultaneously enhance photocarrier generation and prolong photocarrier lifetime through heterogeneous nanoscale VO₂/Pt interfaces. A physical reservoir based on these devices resolves 16 distinct states under 4-bit optical input sequences and achieves an accuracy of 88.5% in sequence-encoded MNIST handwritten-digit classification, compared with 54.8% for pristine VO₂. Ultrafast transient absorption spectroscopy further confirms that Pt NPs reshape the photoexcited carrier dynamics in VO₂, leading to both improved photocarrier generation and an extended dominant carrier lifetime (3.86 ± 0.18 ns vs 2.60 ± 0.03 ns). These results suggest that nanoscale engineering of metal/oxide interfaces offers an effective materials-level strategy for improving temporal information processing in future photonic neuromorphic computing systems.