Electro-optic effect induced in glass waveguides containing a charge-trapping layer

Abstract Artificial synapses that integrate functions of sensing, memory and computing are highly desired for developing brain-inspired neuromorphic hardware. In this work, an optoelectronic synapse based on the ZnO nanowire (NW) transistor is achieved, which can be used to emulate both the short-term and long-term synaptic plasticity. Synaptic potentiation is present when the device is stimulated by light pulses, arising from the light-induced O2 desorption and the persistent photoconductivity behavior of the ZnO NW. On the other hand, synaptic depression occurs when the device is stimulated by electrical pulses in dark, which is realized by introducing a charge trapping layer in the gate dielectric to trap carriers. Simulation of a neural network utilizing the ZnO NW synapses is carried out, demonstrating a high recognition accuracy over 90% after only 20 training epochs for recognizing the Modified National Institute of Standards and Technology (MNIST) digits. The present nanoscale optoelectronic synapse has great potential in the development of neuromorphic visual systems.

Download Full-text

Influence of AlN and GaN Pulse Ratios in Thermal Atomic Layer Deposited AlGaN on the Electrical Properties of AlGaN/GaN Schottky Diodes

Coatings ◽

10.3390/coatings10050489 ◽

2020 ◽

Vol 10 (5) ◽

pp. 489 ◽

Cited By ~ 1

Author(s):

Hogyoung Kim ◽

Seok Choi ◽

Byung Joon Choi

Keyword(s):

Photoelectron Spectroscopy ◽

Schottky Diodes ◽

Charge Trapping ◽

Negative Temperature ◽

Atomic Layer ◽

Algan Layer ◽

Pulse Ratio ◽

Current Voltage ◽

Frenkel Emission ◽

A Charge

Atomic layer deposited AlGaN with different AlN and GaN pulse ratios (2:1, 1:1, and 1:2) was used to prepare AlGaN/GaN Schottky diodes, and their current transport mechanisms were investigated using current–voltage (I–V) and capacitance–voltage (C–V) measurements. Under low reverse bias condition, the sample with the pulse ratio of 2:1 was explained by Poole–Frenkel emission and the negative temperature dependence for the sample with the pulse ratio of 1:2 was associated with the acceptor levels in the AlGaN layer. Fast interface traps at 0.24–0.29 eV were observed for the samples with the pulse ratios of 1:1 and 1:2, whereas bulk traps at ~0.34 eV were observed for the sample with the pulse ratio of 2:1. Higher trap densities were obtained from the C–V hysteresis measurements when the pulse ratios were 1:1 and 1:2, indicating the presence of a charge trapping interfacial layer. According to the X-ray photoelectron spectroscopy spectra, the pulse ratio of 2:1 was found to have less oxygen-related defects in the AlGaN layer.

Download Full-text

Chemical-Vapor-Deposited Graphene as Charge Storage Layer in Flash Memory Device

Journal of Nanomaterials ◽

10.1155/2016/6751497 ◽

2016 ◽

Vol 2016 ◽

pp. 1-6 ◽

Cited By ~ 2

Author(s):

W. J. Liu ◽

L. Chen ◽

P. Zhou ◽

Q. Q. Sun ◽

H. L. Lu ◽

...

Keyword(s):

Flash Memory ◽

Room Temperature ◽

Metal Layer ◽

Chemical Vapor ◽

Charge Trapping ◽

Memory Device ◽

Water Molecules ◽

Oh Groups ◽

Chemical Vapor Deposited ◽

A Charge

We demonstrated a flash memory device with chemical-vapor-deposited graphene as a charge trapping layer. It was found that the average RMS roughness of block oxide on graphene storage layer can be significantly reduced from 5.9 nm to 0.5 nm by inserting a seed metal layer, which was verified by AFM measurements. The memory window is 5.6 V for a dual sweep of ±12 V at room temperature. Moreover, a reduced hysteresis at the low temperature was observed, indicative of water molecules or −OH groups between graphene and dielectric playing an important role in memory windows.

Download Full-text

Graphene Oxide: Graphene Quantum Dot Nanocomposite for Better Memristic Switching Behaviors

Nanomaterials ◽

10.3390/nano10081448 ◽

2020 ◽

Vol 10 (8) ◽

pp. 1448

Author(s):

Lei Li

Keyword(s):

Graphene Oxide ◽

Data Storage ◽

Indium Tin Oxide ◽

Nonvolatile Memory ◽

Conduction Mechanism ◽

Graphene Quantum Dots ◽

Charge Trapping ◽

Reset Voltage ◽

Ultrahigh Density ◽

A Charge

Tristable memristic switching provides the capability for multi-bit data storage. In this study, all-inorganic multi-bit memory devices were successfully manufactured by the attachment of graphene quantum dots (GQDs) onto graphene oxide (GO) through a solution-processable method. By means of doping GQDs as charge-trapping centers, the device indium-tin oxide (ITO)/GO:0.5 wt%GQDs/Ni revealed controllable memristic switching behaviors that were tunable from binary to ternary, and remarkably enhanced in contrast with ITO/GO/Ni. It was found that the device has an excellent performance in memristic switching parameters, with a SET1, SET2 and RESET voltage of −0.9 V, −1.7 V and 5.15 V, as well as a high ON2/ON1/OFF current ratio (103:102:1), and a long retention time (104 s) together with 100 successive cycles. The conduction mechanism of the binary and ternary GO-based memory cells was discussed in terms of experimental data employing a charge trapping-detrapping mechanism. The reinforcement effect of GQDs on the memristic switching of GO through cycle-to-cycle operation has been extensively investigated, offering great potential application for multi-bit data storage in ultrahigh-density, nonvolatile memory.

Download Full-text