Search

Your search keyword '"Zhenhua Tang"' showing total 4 results
Start Over Author "Zhenhua Tang" Journal nanomaterials
4 results on '"Zhenhua Tang"'

1. Neuromorphic Computing of Optoelectronic Artificial BFCO/AZO Heterostructure Memristors Synapses

Author

Zhao-Yuan Fan, Zhenhua Tang, Jun-Lin Fang, Yan-Ping Jiang, Qiu-Xiang Liu, Xin-Gui Tang, Yi-Chun Zhou, and Ju Gao

Subjects
BFCO/AZO, optoelectronic, artificial synapse, neuromorphic computing, Chemistry, QD1-999
Abstract

Compared with purely electrical neuromorphic devices, those stimulated by optical signals have gained increasing attention due to their realistic sensory simulation. In this work, an optoelectronic neuromorphic device based on a photoelectric memristor with a Bi2FeCrO6/Al-doped ZnO (BFCO/AZO) heterostructure is fabricated that can respond to both electrical and optical signals and successfully simulate a variety of synaptic behaviors, such as STP, LTP, and PPF. In addition, the photomemory mechanism was identified by analyzing the energy band structures of AZO and BFCO. A convolutional neural network (CNN) architecture for pattern classification at the Mixed National Institute of Standards and Technology (MNIST) was used and improved the recognition accuracy of the MNIST and Fashion-MNIST datasets to 95.21% and 74.19%, respectively, by implementing an improved stochastic adaptive algorithm. These results provide a feasible approach for future implementation of optoelectronic synapses.

Published
2024
Full Text
View/download PDF

2. Enhancement of Resistive Switching Performance in Hafnium Oxide (HfO2) Devices via Sol-Gel Method Stacking Tri-Layer HfO2/Al-ZnO/HfO2 Structures

Author

Yuan-Dong Xu, Yan-Ping Jiang, Xin-Gui Tang, Qiu-Xiang Liu, Zhenhua Tang, Wen-Hua Li, Xiao-Bin Guo, and Yi-Chun Zhou

Subjects
HfO2, Al-ZnO, sol–gel method, resistive switching, multi-level memory, conductive filament, Chemistry, QD1-999
Abstract

Resistive random-access memory (RRAM) is a promising candidate for next-generation non-volatile memory. However, due to the random formation and rupture of conductive filaments, RRMS still has disadvantages, such as small storage windows and poor stability. Therefore, the performance of RRAM can be improved by optimizing the formation and rupture of conductive filaments. In this study, a hafnium oxide-/aluminum-doped zinc oxide/hafnium oxide (HfO2/Al-ZnO/HfO2) tri-layer structure device was prepared using the sol–gel method. The oxygen-rich vacancy Al-ZnO layer was inserted into the HfO2 layers. The device had excellent RS properties, such as an excellent switch ratio of 104, retention of 104 s, and multi-level storage capability of six resistance states (one low-resistance state and five high-resistance states) and four resistance states (three low-resistance states and one high-resistance state) which were obtained by controlling stop voltage and compliance current, respectively. Mechanism analysis revealed that the device is dominated by ohmic conduction and space-charge-limited current (SCLC). We believe that the oxygen-rich vacancy concentration of the Al-ZnO insertion layer can improve the formation and rupture behaviors of conductive filaments, thereby enhancing the resistive switching (RS) performance of the device.

Published
2022
Full Text
View/download PDF

3. Excellent Bipolar Resistive Switching Characteristics of Bi4Ti3O12 Thin Films Prepared via Sol-Gel Process

Author

Yan-Ping Jiang, Qiu-Xiang Liu, He-Chun Zhou, Zhenhua Tang, Wen-Hua Li, and Xin-Gui Tang

Subjects
Materials science, business.industry, resistive switching, conductive filaments, thin film, General Chemical Engineering, Memristor, Thermal conduction, Ferroelectricity, Space charge, Article, Resistive random-access memory, law.invention, oxygen vacancies, Chemistry, X-ray photoelectron spectroscopy, law, Bi4Ti3O12, Optoelectronics, General Materials Science, Thin film, business, Electrical conductor, QD1-999
Abstract

Herein, Bi4Ti3O12 (BIT) ferroelectric thin films were fabricated into Au/BIT/LaNiO3/Si structures to demonstrate their memristor properties. Repeatable and stable bipolar resistive switching (RS) characteristics of the device are first reported in this work. The switching ratio of the device annealed in air reached approximately 102 at 0.1 and −0.1 V. The RS performance was not significantly degraded after 100 consecutive cycles of testing. We also explored the factors affecting the RS behavior of the device. By investigating the RS characteristics of the devices annealed in O2, and in combination with XPS analysis, we found that the RS properties were closely related to the presence of oxygen vacancies. The devices annealed in air exhibited a markedly improved RS effect over those annealed in O2. According to the slope fitting, the conduction mechanism of the device was the ohmic conduction and space charge limited current (SCLC). This study is the first to successfully apply BIT ferroelectric films to the RS layers of memristors. Additionally, a theory of conductive filaments is proposed to adequately explain the relationship between RS behavior and oxygen vacancies, providing meaningful inspiration for designing high-quality resistive random access memory devices.

Published
2021
Full Text
View/download PDF

4. Resistive Switching Characteristics of HfO2 Thin Films on Mica Substrates Prepared by Sol-Gel Process

Author

Lun-Quan Wang, Zhenhua Tang, Wen-Hua Li, Qiu-Xiang Liu, Chao-Feng Liu, Xin-Gui Tang, Hui Tang, and Yan-Ping Jiang

Subjects
010302 applied physics, Materials science, Annealing (metallurgy), General Chemical Engineering, Analytical chemistry, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, oxygen defect, Article, Resistive random-access memory, lcsh:Chemistry, Chemical state, X-ray photoelectron spectroscopy, lcsh:QD1-999, 0103 physical sciences, General Materials Science, Mica, conduction mechanism, Thin film, high/low resistance, 0210 nano-technology, resistance switching, Sol-gel, Monoclinic crystal system
Abstract

The resistive switching (RS) characteristics of flexible films deposited on mica substrates have rarely been reported upon, especially flexible HfO2 films. A novel flexible Au/HfO2/Pt/mica resistive random access memory device was prepared by a sol-gel process, and a Au/HfO2/Pt/Ti/SiO2/Si (100) device was also prepared for comparison. The HfO2 thin films were grown into the monoclinic phase by the proper annealing process at 700 &deg, C, demonstrated by grazing-incidence X-ray diffraction patterns. The ratio of high/low resistance (off/on) reached 1000 and 50 for the two devices, respectively, being relatively stable for the former but not for the latter. The great difference in ratios for the two devices may have been caused by different concentrations of the oxygen defect obtained by the X-ray photoelectron spectroscopy spectra indicating composition and chemical state of the HfO2 thin films. The conduction mechanism was dominated by Ohm&rsquo, s law in the low resistance state, while in high resistance state, Ohmic conduction, space charge limited conduction (SCLC), and trap-filled SCLC conducted together.

Published
2019

Catalog

Books, media, physical & digital resources
See catalog results