A Low‐Toxic Colloidal Quantum Dots Sensitized IGZO Phototransistor Array for Neuromorphic Vision Sensors

Abstract

The rapid development of optoelectronic devices with biomimetic synaptic behavior holds significant potential for neuromorphic visual applications. However, considerable challenges remain including convenient device fabrication and low toxicity materials innovation. Here, a heterojunction phototransistor is constructed using low‐toxic CuZnInSSe (CIZS) colloidal quantum dots and amorphous InGaZnO (IGZO), which demonstrates high specific detectivity of 3.4 × 1015 Jones in visible light spectrum. Moreover, it is found that the photoresponse speed can be controlled via a ligand exchange treatment, through that the response speed can be adjusted from 0.3 to 11 s. This enables the device to operate in two distinct modes: a typical fast sensing mode and a neuromorphic visual mode. In the neuromorphic visual mode, the device's synaptic behavior can be tuned by manipulating light pulse intensity, frequency, wavelength, and gate voltage. As a demonstration, a phototransistor array effectively implements image pre‐processing functions, including color recognition, visual memorizing, and forgetting.

A CsPbI3/PCBM Phototransistor with Low Dark Current by Suppressing Ion Migration

“…Phototransistors have obtained an increasing amount of research attention owing to their advantages of compatibility with transistor circuit manufacture and photodetection gain effect [1][2][3][4][5][6]. Over recent years, perovskite semiconductors have been developed remarkably, showing their high optoelectronic performance, such as quantum efficiency of over 90% and carrier lifetime of over 1 µs [7][8][9][10].…”