Photosensitive Schottky Barrier Diode Based on Cu/p-SnSe Thin Film Fabricated by Thermal Evaporation

Tin Selenide (SnSe), a group IV-VI compound semiconductor material is used to fabricate various solid state devices such as memory switching devices, P-N junction diodes, Schottky barrier diodes, etc. In...

Compliance Current-dependent Dual-functional Unipolar and Threshold Resistive Switching in Silver Nanowires-egg Albumen Composites-based Device

The continued exploration of novel synthetic memristive materials with multifunctional properties is critical for future synapse-emulating circuits and electronic devices in the field of next-generation neuromorphic computing applications. In this work, the silver nanowires (AgNWs)-Egg albumen composites have been integrated as a resistive switching layer in the Ag/AgNWs-Egg albumen/Ag planar structure and exhibits both unipolar (memory) switching and threshold switching functions. The device in unipolar switching regime demonstrates an ON/OFF ratio above 105, a low resistance state of about 1.2 KΩ and a high resistance state of about 120 MΩ. Finally, a mechanism in combination with the conductive filament theory and a tunnelling conduction mechanism is proposed to explain the resistive switching behavior. The devices are prepared by simple and low-cost techniques, which make such devices appealing for future electronic applications.

Demonstration of Threshold Switching and Bipolar Resistive Switching in Ag/SnOx/TiN Memory Device

In this work, we observed the duality of threshold switching and non-volatile memory switching of Ag/SnOx/TiN memory devices by controlling the compliance current (CC) or pulse amplitude. The insulator thickness and chemical analysis of the device stack were confirmed by transmission electron microscope (TEM) images of the Ag/SnOx/TiN stack and X-ray photoelectron spectroscopy (XPS) of the SnOx film. The threshold switching was achieved at low CC (50 μA), showing volatile resistive switching. Optimal CC (5 mA) for bipolar resistive switching conditions with a gradual transition was also found. An unstable low-resistance state (LRS) and negative-set behavior were observed at CCs of 1 mA and 30 mA, respectively. We also demonstrated the pulse operation for volatile switching, set, reset processes, and negative-set behaviors by controlling pulse amplitude and polarity. Finally, the potentiation and depression characteristics were mimicked by multiple pulses, and MNIST pattern recognition was calculated using a neural network, including the conductance update for a hardware-based neuromorphic system.

Computerized LEXTOMM Battery (Language, EXecutive functions, Theory Of Mind, episodic Memory)

We present a computerize battery constructed to evaluate behavioral performances for language, declarative memory, executive functions and social cognition abilities. This battery was created to evaluate cognitive outcomes in adults who underwent hemispherotomy as a clinical treatment of Rasmussen Encephalitis (RE) in their childhood and have been tested in a group of healthy participants (n= 88). LEXTOMM battery can be used for cognitive assessment of any type of population and allow the collection of behavioral performances in terms of accuracy and reaction times. LEXTOMM battery is composed of six language tasks allowing to assess six different linguistic abilities such as lexical storage, semantics, phonology, syntax, prosody perception and production. Different input modalities are proposed for these tasks (picture, written and auditory modality). A specific task allowing the assessment of the language generation and declarative memory interaction is also proposed. The battery also included a visual control categorization task is proposed in order to assess decision-making baseline. Moreover, LEXTOMM also includes four tasks allowing the assessment of the executive functions. More specifically we included tasks allowing the evaluation of four executive processes: updating in working memory, switching/flexibility, sustained attention and inhibition. Finally, the battery includes a theory of mind abilities task. All tasks were developed using the E-Prime 3.0 software (E-Prime Psychology Software Tools Inc., Pittsburgh, USA), running on a PC. Before each task, a training session is included, with several stimuli that differ from those presented during the experiment. This training allows participants to understand the instructions and get familiarized with each task. Hereafter, we describe the procedures and tasks included in LEXTOMM, in the following order: low-level visual categorization, language, language in interaction with declarative memory, executive functions and social cognition/theory of mind.

A Novel Poly-N-Epoxy Propyl Carbazole Based Memory Device

Generally, polymer-based memory devices store information in a manner distinct from that of silicon-based memory devices. Conventional silicon memory devices store charges as either zero or one for digital information, whereas most polymers store charges by the switching of electrical resistance. For the first time, this study reports that the novel conducting polymer Poly-N-Epoxy-Propyl Carbazole (PEPC) can offer effective memory storage behavior. In the current research, the electrical characterization of a single layer memory device (metal/polymer/metal) using PEPC, with or without doping of charge transfer complexes 7,7,8,8-tetra-cyanoquino-dimethane (TCNQ), was investigated. From the current–voltage characteristics, it was found that PEPC shows memory switching effects in both cases (with or without the TCNQ complex). However, in the presence of TCNQ, the PEPC performs faster memory switching at relatively lower voltage and, therefore, a higher ON and OFF ratio (ION/IOFF ~ 100) was observed. The outcome of this study may help to further understand the memory switching effects of conducting polymer.

Near-Infrared Heterojunction Field Modulated Phototransistors with Distinct Photodetection/Photostorage Switching Feature for Artificial Visuals

With the rising demand of recording, computing and image capture, advanced optoelectronic detection, storage and logic devices are highly pursued. Nevertheless, multi-functional vision chip based on infrared detection and memory switching has never been demonstrated. Here, by utilizing the electronic extraction layer ZnO and face-on orientation of D-A, we exhibit the broadband visible to near-infrared photo-response and photo-storage characters on graphene phototransistor. Functions as photodetection and photo-storage can be switched with the variation of gate voltage. The device demonstrates high photo-responsivity up to 1.88 × 106 A/W at 895 nm corresponding detectivity of 4.8 × 1012 Jones. Importantly, the rewritable and switching infrared optoelectronic memory function can be achieved with good retention over 104 s. The both retinomorphic vision and memorial preprocessing in artificial visual are simultaneously realized by photodetection/photostorage switching property. Such nearly all-solution processes in our phototransistors may open up the path for the large-scale and easy manufacturing infrared multifunctional bio-optoelectronic device.

Sensory experience modulates the reorganisation of temporal auditory regions for executive processing

Crossmodal plasticity refers to the reorganisation of sensory cortices in the absence of their main sensory input. Understanding this phenomenon provides insights into brain function and its potential for change and enhancement. Using fMRI, we investigated how early deafness and consequent varied language experience influence crossmodal plasticity and the organisation of executive functions (EF) in the adult brain. Results from four visual EF tasks (working memory, switching, planning, inhibition) show that, as a function of the degree of deafness, deaf individuals specifically recruit “auditory” regions during switching. This recruitment correlates with performance, highlighting its functional relevance. We also observed recruitment of auditory temporal regions during planning, but only in deaf individuals with the highest language scores, suggesting differential use of linguistic skills to support EF. Our results show executive processing in typically sensory regions, suggesting that the development and ultimate role of brain regions are influenced by perceptual environmental experience.