IGZO/HfO_x Heterojunction Optoelectronic Memristor With Multiwavelength Response for Neuromorphic Visual System

Wide-bandgap metal oxide semiconductors possess suitable characteristics for neuromorphic visual systems, including high light absorption efficiency and persistent photoconductivity. However, their limited responsivity to low-energy photons has hindered applications requiring color discrimination and multi-spectral signal processing. To address this challenge, we developed an oxygen-deficient IGZO/HfO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> heterojunction memristor with multiwavelength response. The device demonstrates synaptic functionality under 350-680 nm illuminations, such as excitatory postsynaptic current, paired-pulse facilitation, and image perception-memory integration. Leveraging on the optical potentiation and electrical depression characteristics, the color image recognition has achieved 85.8% accuracy in an artificial neural network. The visible-light response of IGZO is ascribed to the oxygen defect energy levels capable of trapping photo-electrons. This work provides a viable pathway for developing high-efficiency neuromorphic vision systems using wide-bandgap oxide semiconductors with full-spectrum detection capabilities.