Hetero-Integrated InGaAs Photodiode and Oxide Memristor-Based Artificial Optical Nerve for In-Sensor NIR Image Processing

Abstract

In-sensor computing is an emerging architectural paradigm that fuses data acquisition and processing within a sensory domain. The integration of multiple functions into a single domain reduces the system footprint while it minimizes the energy and time for data transfer between sensory and computing units. However, it is challenging for a simple and compact image sensor array to achieve both sensing and computing in each pixel. Here, this work demonstrates a focal plane array with a heterogeneously integrated one-photodiode one-resistor (1P-1R)-based artificial optical neuron that emulates the sensing, computing, and memorization of a biological retina system. This work employs an InGaAs photodiode featuring a high responsivity and a broad spectrum that covers near-infrared (NIR) signals and employs an HfO2 memristor as the artificial synapse to achieve the computing/memorization in an analog domain. Using the fabricated focal plane array integrated with an artificial neural network, this work performs in-sensor image identification of finger veins driven by NIR light illumination (≈84 % accuracy). The proposed in-sensor image computing architecture that broadly covers the NIR spectrum offers widespread application of focal plane array for computer vision, neuromorphic computing, biomedical engineering, etc.