Infrared Polarization‐Sensitive Visual Neuromorphic Synapse Based on 2D PdSe 2 /Ta 2 NiS 5 Heterojunction

Mapping the Dynamic Transfer Functions of Epigenome Editing

III-V compound semiconductors are indispensable materials for today's high-end electronic and optoelectronic devices and are being explored for next-generation transistor logic and quantum technologies. III-V surfaces and interfaces play the leading role in determining device performance, and therefore, methods to control their electronic properties have been developed. Typically, surface passivation studies demonstrated how to limit the density of surface states. Strain has been widely used to improve the electronic transport properties and optoelectronic properties of III-Vs, but the potential of this technology to modify the surface properties still remains to be explored. Here we show that uniaxial stress induces a shift in the energy of the surface states of III-V nanowires, modifying their electronic properties. We demonstrate this phenomenon by modulating the conductivity of InAs nanowires over 4 orders of magnitude with axial strain ranging between -2.5% in compression and 2.1% in tension. The band bending at the surface of the nanostructure is modified from accumulation to depletion reversibly and reproducibly. We provide evidence of this physical effect using a combination of electrical transport measurement, Raman spectroscopy, band-structure modeling, and technology computer aided design (TCAD) simulations. With this methodology, the deformation potentials for the surface states are quantified. These results reveal that strain technology can be used to shift surface states away from energy ranges in which device performance is negatively affected and represent a novel route to engineer the electronic properties of III-V devices.

A pulsed discharge lamp containing Hg vapor suitable for kinetic spectroscopy in the nanosecond time range is described. The spectral output is practically the same as that from a conventional low pressure mercury resoance lamp. The light intensity of the 253.7 nm resonance line is about 1010 photon/pulse. The width of light pulses is about 10 ns, except at 253.7 nm, which pulse width is about 40 ns. The repetition rate is 5–10 kHz. Quenching rates of Hg(3P1) atoms by H2, C2H4, CO, and NH3 are obtained by measuring decay rates of the 253.7 nm resonance line.

A pulse-stream signaling mechanism is described that is analogous to that found in natural neural systems. Previous work has resulted in the development of synthetic neural networks implemented as VLSI devices using pulse streams to represent neural states and a time-chopping technique to implement multiplication by synaptic weights. Synaptic weights are stored on-chip in digital memory. An alternative method for representing synaptic weights is described which uses dynamic storage capacitors to hold the charge proportional to synaptic weight. The capacitive storage devices are refreshed from off-chip digital RAM via a digital-to-analog converter. The presence, absence, and rate of pulse firing of the neuron are used to represent its state. Multiplication of a neuron state by a synaptic weight is performed by modifying the width of individual pulses passing through the synapse. A circuit that performs this function is described. The small synaptic circuit that results allows relatively high levels of integration in comparison to other programmable silicon neural forms. >

Hybrid ac-current sensor based on the time modulation of an autonomous light source

Engineering of TiN/ZnO/SnO2/ZnO/Pt multilayer memristor with advanced electronic synapses and analog switching for neuromorphic computing

Flexible transparent InZnO synapse transistor based on Li1.3Al0.3Ti0.7(PO4)3/polyvinyl pyrrolidone nanocomposites electrolyte film for neuromorphic computing

The exploration of synaptic plasticity in metal-oxide-based ferroelectric thin-film transistors has been limited. As a perovskite ferroelectric material, LiNbO3 is widely studied; but its potential use as a neuromorphic device, like synaptic transistors, has not been realized. In this study, a solution-processed ferroelectric thin-film transistor (FeTFT) with an alternating layer of LiNbO3 and Li5AlO4 as a gate dielectric has been fabricated. This configuration reduces the depolarization field by leveraging the large ionic polarization of Li+ ions in the Li5AlO4 layer, while the wide bandgap helps mitigate the leakage current. FeTFT exhibits impressive transistor performance, including a saturation mobility of 0.478 cm2V-1 s-1, an on/off ratio of 3.08 × 103, and a low trap-state density of 1.3 × 1013 cm-2. Moreover, the device demonstrates good memory retention, retaining information for nearly 1 day. It successfully emulates synaptic plasticity, specifically short-term plasticity and long-term plasticity. Besides, a 94% training accuracy has been achieved through artificial neural network simulation. Notably, the FeTFT consumes minimal power, with energy consumption of approximately 3.09 nJ per synaptic event, which is remarkably low compared to other reported solution-processed FeTFT devices.

Development of artificial opto‐electronic synaptic devices plays a crucial role for the practical implementation of energy‐efficient, parallel processing of human brain. In this article, two terminal inter‐digitated devices are fabricated on Gallium oxide (Ga2O3) thin films grown on sapphire substrates by pulsed laser deposition (PLD) technique to study its ability to mimic biological synaptic behaviors. The layers are found to exhibit long persistent photo‐conductivity (PPC) effect, which is identified to be the key parameter to replicate the behavior of biological synapses. Channel resistance and PPC time constants should also be optimized to improve the efficiency of response and energy consumption of synaptic devices. It has been observed that both conductivity and the PPC decay time of Ga2O3‐films can be controlled by varying oxygen pressure and growth temperature (TG). These devices demonstrate their ability to perform paired pulse facilitation (PPF) at very low applied bias in mV‐range. They can mimic biological synapses showing short‐to‐long‐term memory transition (STM‐to‐LTM) and learning‐forgetting behavior. One of these devices is found to show synaptic behavior with the energy consumption of as low as 71fJ electrical and 21nJ optical per synaptic event. These findings thus strengthen the candidature of Ga2O3 films for the development of next‐generation opto‐electronic neuromorphic devices and systems.

Closely mimicking the hierarchical structural topology with emerging behavioral functionalities of biological neural networks in neuromorphic devices is considered of prime importance for the realization of energy-efficient intelligent systems. In this article, we report an artificial synaptic network (ASN) comprising of hierarchical structures of isolated Al and Ag micro-nano structures developed via the utilization of a desiccated crack pattern, anisotropic dewetting, and self-formation. The strategically designed ASN, despite having multiple synaptic junctions between electrodes, exhibits a threshold switching (Vth ∼ 1-2 V) with an ultra-low energy requirement of ∼1.3 fJ per synaptic event. Several configurations of the order of hierarchy in the device architecture are studied comprehensively to identify the importance of the individual metallic components in contributing to the threshold switching and energy-minimization. The emerging potentiation behavior of the conductance (G) profile under electrical stimulation and its permanence beyond are realized over a wide current compliance range of 0.25 to 300 μA, broadly classifying the short- and long-term potentiation grounded on the characteristics of filamentary structures. The scale-free correlation of potentiation in the device hosting metallic filaments of diverse shapes and strengths could provide an ideal platform for understanding and replicating the complex behavior of the brain for neuromorphic computing.

We report measurements of the ac polarizabilities of ultracold ground-state\n$^{23}\\rm{Na}^{87}\\rm{Rb}$ molecules. While the polarizability of the ground\nrotational state $J = 0$ is isotropic, that of the first excited rotational\nstate $J = 1$ is anisotropic and depends strongly on the light polarization\nangle. We obtain both polarizabilities precisely by combining trap oscillation\nfrequency measurement and high resolution rotational spectroscopy driven by\nmicrowave. With the optimized light polarization angle and intensity\ncombination, the nonuniformity of the differential ac Stark shift between the\ntwo rotational states is minimized and the rotational coherence time is\nobserved to be the longest.\n

Unpinned behavior of the Fermi level and photovoltage on p-(100) GaAs surface facilitated by deposition of cesium

The variation of electronic properties with the doping concentration of modulation-doped AlxGa1−xAs–GaAs double quantum wells

Thermo chemical stability of cadmium sulfide nanoparticles under intense pulsed light irradiation and high temperatures

In this paper, a theoretical simulation based on a finite-difference time-domain method (FDTD) shows that the solar absorber can reach ultra-broadband and high-efficiency by refractory metals titanium (Ti) and titanium nitride (TiN). In the absorption spectrum of double-size cross-shaped absorber, the absorption bandwidth of more than 90% is 1182 nm (415.648–1597.39 nm). Through the analysis of the field distribution, we know the physical mechanism is the combined action of propagating plasmon resonance and local surface plasmon resonance. After that, the paper has a discussion about the influence of different structure parameters, polarization angle and angle of incident light on the absorptivity of the absorber. At last, the absorption spectrum of the absorber under the standard spectrum of solar radiance Air Mass 1.5 (AM1.5) is studied. The absorber we proposed can be used in solar energy absorber, thermal photovoltaics, hot-electron devices and so on.