Photopic Adaptation Mimicked by YO-Based Optoelectronic Memristor for Neuromorphic Visual System.

Visual adaptation is one of the most significant features that helps organisms process complicated image information in time-varying environments. Emulating this function is highly desirable for energy-efficient image perception. In this work, we demonstrate an yttrium oxide (YO)-based optoelectronic memristor and emulate photopic adaptation behavior in a single device. Decay amplitude and photosensitivity are indexed to describe the time-dependent characteristics of photopic adaptation. An intensity-dependent characteristic, namely Weber's law, is also investigated in this work. Photopic adaptation originates from the trapping of photogenerated carriers in oxygen vacancies. Based on photopic adaptation behavior, a neuromorphic vision system capable of adapting to environmental brightness is constructed using the proposed optoelectronic memristor array. Memristor arrays can emulate sensing and adaptation functions in order to enhance images against bright backgrounds. Our work provides a feasible pathway toward self-adaptive neuromorphic vision systems.