IGZO/CsPbBr₃-Nanoparticles/IGZO Neuromorphic Phototransistors and Their Optoelectronic Coupling Applications

Abstract

Optoelectronic synaptic devices are of great scientific and practical importance because of various potential applications such as ocular simulating and optical−electrical managers based on a new optoelectronic coupling mechanism. In this work, we design a novel channel layer with p-type CsPbBr 3 nanoparticles (NPs) buried in an InGaZnO (IGZO) film to construct the corresponding thin-film transistors (TFTs), which exhibits intense improvement in visible-light photosensitivity and synaptic plasticity as compared to the pure IGZO counterpart. Specifically, the composite device is able to exhibit versatile synaptic behavior under light stimuli with density as low as 0.12 μW/cm 2 and with the gain 5−20 times higher than that of the IGZO TFT in the visible-light region. Based on the band alignment between the IGZO and NPs, the excitation and decay processes of intrinsic and photoinduced carriers are discussed. Moreover, owing to the gate bias control in a threeterminal configuration, our TFT synapses can imitate complex biological behaviors including the famous "Pavlov's dog" experiment and the "reward and punishment mechanism" of the brain via editing the gate voltage/light pulse stimuli.

Emerging Optical In‐Memory Computing Sensor Synapses Based on Low‐Dimensional Nanomaterials for Neuromorphic Networks

“…[35,120,121] The photoinduced ionization resulted in the neutral oxygen vacancies with a positive charge due to the persistent photoconductivity (PPC) characteristic of the oxide semiconductor and these ionized vacancies transferred back to the neutralized state after removing the optical stimuli. [35,[120][121][122] The ionized and deionized processes could be represented by the following equations [35] V…”

“…[ 35,120,121 ] The photoinduced ionization resulted in the neutral oxygen vacancies with a positive charge due to the persistent photoconductivity (PPC) characteristic of the oxide semiconductor and these ionized vacancies transferred back to the neutralized state after removing the optical stimuli. [ 35,120–122 ] The ionized and deionized processes could be represented by the following equations [ 35 ] where is the insulating oxygen vacancy without charge, is the bound oxygen, is the hole with a positive charge, is the interstitial oxygen, is the electron with a negative charge, and is the activation energy.…”

“…[ 121 ] Duan et al also investigated the optical IMSC performance of a three‐terminal transistor with perovskite (PVK) NPs and IGZO materials. [ 122 ] Due to the built‐in electric field induced by optical stimuli, photoinduced electron–hole pairs were separated. Compared with the n‐type IGZO, the p‐type CsPbBr 3 ‐NPs had a deeper Fermi level ( E f ), which promoted electrons in IGZO transfer to CsPbBr 3 ‐NPs and then E f of IGZO drifted in a downward direction near the interface of IGZO/CsPbBr 3 ‐NPs.…”

Bio‐Inspired 3D Artificial Neuromorphic Circuits

“…[ 232,233 ] An enrichment of related investigations regarding synaptic transistors based on MOSs have also been recently conducted. [ 234–242 ] In additional to single gate configuration and MOSs as the functional material, multiple‐gate synaptic transistors based on 2D materials have drawn tremendous research efforts as well. [ 243–249 ] As illustrated in Figure 9b, Chen et al.…”

“…[232,233] An enrichment of related investigations regarding synaptic transistors based on MOSs have also been recently conducted. [234][235][236][237][238][239][240][241][242] In additional to single gate configuration and MOSs as the functional material, multiple-gate synaptic transistors based on 2D materials have drawn tremendous research efforts as well. [243][244][245][246][247][248][249] As illustrated in Figure 9b, Chen et al recently combined a double-gate configuration with intrinsic polarity of 2D materials to perform logic operations in a single synaptic device, which realizes XNOR gate using ambipolar tungsten diselenide (WSe 2 ), NOR gate with black phosphorus, as well as OR and AND gates via molybdenum disulfide (MoS 2 ).…”