Artificial visual perception neural system using a solution-processable MoS2-based in-memory light sensor

Abstract

Optoelectronic devices are advantageous in in-memory light sensing for visual information processing, recognition, and storage in an energy-efficient manner. Recently, in-memory light sensors have been proposed to improve the energy, area, and time efficiencies of neuromorphic computing systems. This study is primarily focused on the development of a single sensing-storage-processing node based on a two-terminal solution-processable MoS2 metal–oxide–semiconductor (MOS) charge-trapping memory structure—the basic structure for charge-coupled devices (CCD)—and showing its suitability for in-memory light sensing and artificial visual perception. The memory window of the device increased from 2.8 V to more than 6 V when the device was irradiated with optical lights of different wavelengths during the program operation. Furthermore, the charge retention capability of the device at a high temperature (100 °C) was enhanced from 36 to 64% when exposed to a light wavelength of 400 nm. The larger shift in the threshold voltage with an increasing operating voltage confirmed that more charges were trapped at the Al2O3/MoS2 interface and in the MoS2 layer. A small convolutional neural network was proposed to measure the optical sensing and electrical programming abilities of the device. The array simulation received optical images transmitted using a blue light wavelength and performed inference computation to process and recognize the images with 91% accuracy. This study is a significant step toward the development of optoelectronic MOS memory devices for neuromorphic visual perception, adaptive parallel processing networks for in-memory light sensing, and smart CCD cameras with artificial visual perception capabilities.

Solution-Processable and Printable Two-Dimensional Transition Metal Dichalcogenide Inks

“…Optoelectronic memory devices can also be fabricated using solutionprocessable MoS 2 in a metal−oxide−semiconductor (MOS) structure (Figure 18e). 237 The memory window of the device is enlarged from 2.8 to 6.0 V under light illuminations due to the electrons generated at the MoS 2 layer and Al 2 O 3 /MoS 2 interface (Figure 18f). The MoS 2 MOS optoelectronic memory devices can process and recognize the images with 91% accuracy by inference computation.…”

Recent Progress of Polymeric Dielectrics in Molybdenum Disulfide-Based Devices

“…Thus, it is urgent to find a new class of materials to overcome these technical problems. With the nature of ultrathin thickness, dangling-free bonds and tunable band structure, transition metal dichalcogenides (TMDCs) have shown excellent electrical properties, unique optoelectronic properties, and mechanical flexibility that could be transferred to arbitrary substrates, which are becoming one of the most promising materials to replace traditional silicon-based materials. − Thereinto, molybdenum disulfide (MoS 2 ) with a typical layered structure is widely studied. − According to current progress, MoS 2 possesses the thickness-dependent energy band to widen its absorption spectrum and the large surface-to-volume ratio to assist charge trapping, which lay a good foundation for the development of optoelectronic devices for sensors, − displays, − recognition, − and other diversified applications. − Furthermore, air-stabilized MoS 2 could overcome the phonon scattering through the interface engineering to obtain ultrahigh electrical properties at room temperature and achieve the large-size growth by the regulation of preparation process, which provide advantages for the development of large-scale miniaturized integrated circuits. , Markedly, MoS 2 -based flexible integrated logic circuits as the optimization of the growth process have been successfully studied, which obtained good device yield and excellent electrical performance with the mobility of 55 cm 2 V –1 s –1 , high on/off ratios of 10 10 , and current densities of 35 μA μm –1 …”

Concomitant Light-Reversible Magnetic Response in Multiferroic Oxide Heterostructures for Multiphysics Applications

“…The range of stimuli encompasses magnetic and electric fields, light irradiation, mechanical stress, heat, and chemical reactions, unveiling a set of functionalities in the same material. − This trajectory finds its embodiment in devices characterized by their simplicity and cost-effectiveness, within which the photostimulation offers immediate and accurate responses in a controllable fashion. Photostimulation’s unique capacity to provide monitorable responses sans circuitry or substantial thermal impacts positions it at the forefront of industrial and technological innovation, boosting the development of light-driven devices across various fields. − …”