scholarly journals The effect of content and thickness of chitosan thin films on resistive switching characteristics

2020 ◽  
Vol 23 (3) ◽  
pp. 632-639
Author(s):  
Phuc Dinh Do ◽  
Tu Uyen Thi Doan ◽  
Tap Duy Tran ◽  
Dung Van Hoang ◽  
Kim Ngoc Pham

Introduction: Nowadays, a resistive switching memory using biological, transparent, and environmentally friendly materials is appreciated as the tendency of science and technology, especially in the field of electronic devices. Chitosan (CS), having dominant characteristics such as non-toxic, biocompatible and large capacity, plays as a switching medium in resistive random access memory devices (RRAM). Methods: In our study, CS film was fabricated onto a commercial substrate (FTO) using a simple spin coating method, and the top electrode (Ag) was deposited by a direct-current sputtering technique. Results: The Ag/CS/FTO devices shown the bipolar switching behavior when applying sequence voltage from -1.5 to 2V with the set process in the negative bias and the reset process in the positive bias. The content (0.2, 0.5, and 0.8 wt%) and thickness (100, 300, 500 nm) of chitosan film significantly affect the resistive switching performance. The devices with 0.5 wt%/v concentration and 300 nm-thickness of CS have shown better efficiency than the others with endurance over 100 sweeping cycles and ON/OFF ratio at ca. 2x10 times. Conclusions: It is found that the chitosan material has a large potential candidate for applications in optoelectronic devices.

2010 ◽  
Vol 1250 ◽  
Author(s):  
Jung Won Seo ◽  
Seung Jae Baik ◽  
Sang Jung Kang ◽  
Koseng Su Lim

AbstractWe report resistive switching characteristics in Pt/ZnO/Pt devices where ZnO thin film is fabricated at various oxygen conditions. With the increase of oxygen contents in ZnO thin film, the forming voltage is gradually increased while reset and set voltages are almost unchanged. We also investigated the effect of top electrodes on resistive switching of top electrode/ZnO/Pt device. For a Pt/ZnO/Pt device, it exhibits the excellent resistive switching behavior due to high electrical field of the well-defined Schottky barrier. For Al/ZnO/Pt device, little resistive switching phenomena were occurred due to leakage current of the weak Schottky (or Ohmic) contact.


2016 ◽  
Vol 4 (46) ◽  
pp. 10967-10972 ◽  
Author(s):  
Sujaya Kumar Vishwanath ◽  
Jihoon Kim

The all-solution-based memory devices demonstrated excellent bipolar switching behavior with a high resistive switching ratio of 103, excellent endurance of more than 1000 cycles, stable retention time greater than 104s at elevated temperatures, and fast programming speed of 250 ns.


2007 ◽  
Vol 124-126 ◽  
pp. 603-606
Author(s):  
Sang Hee Won ◽  
Seung Hee Go ◽  
Jae Gab Lee

Simple process for the fabrication of Co/TiO2/Pt resistive random access memory, called ReRAM, has been developed by selective deposition of Co on micro-contact printed (μ-CP) self assembled monolayers (SAMs) patterns. Atomic Layer Deposition (ALD) was used to deposit TiO2 thin films, showing its ability of precise control over the thickness of TiO2, which is crucial to obtain proper resistive switching properties of TiO2 ReRAM. The fabrication process for Co/TiO2/Pt ReRAM involves the ALD of TiO2 on sputter-deposited Pt bottom electrode, followed by μ-CP with SAMs and then selective deposition of Co. This results in the Co/TiO2/Pt structure ReRAM. For comparison, Pt/TiO2/Pt ReRAM was produced and revealing the similar switching characteristics as that of Co/TiO2/Pt, thus indicating the feasibility of Co replacement with Pt top electrode. The ratios between the high-resistance state (Off state) and the low-resistance state (On state) were larger than 102. Consequently, the selective deposition of Co with μ-CP, newly developed in this study, can simplify the process and thus implemented into the fabrication of ReRAM.


2011 ◽  
Vol 1292 ◽  
Author(s):  
Jung Won Seo ◽  
Seung Jae Baik ◽  
Sang Jung Kang ◽  
Koeng Su Lim

ABSTRACTThis report covers the resistive switching characteristics of cross-bar type semi-transparent (or see-through) resistive random access memory (RRAM) devices based on ZnO. In order to evaluate the transmittance of the devices, we designed the memory array with various electrode sizes and spaces between the electrodes. To prevent read disturbance problems due to sneak currents, we employed a metal oxide based p-NiO/n-ZnO diode structure, which exhibited good rectifying characteristics and high forward current density. Based on these results, we found that the combined metal oxide diode/RRAM device could be promising candidate with suppressed read disturbances of cross-bar type ZnO RRAM device.


2011 ◽  
Vol 1337 ◽  
Author(s):  
S. Gorji Ghalamestani ◽  
L. Goux ◽  
D.E. Díaz-Droguett ◽  
D. Wouters ◽  
J. G. Lisoni

ABSTRACTWe investigated the resistive switching behavior of WOx films. WOx was obtained from the thermal oxidation of W thin layers. The parameters under investigation were the influence of the temperature (450-500 °C) and time (30-220 s) used to obtain the WOx on the resistive switching characteristics of Si\W\WOx\Metal_electrode ReRAM cells. The metal top electrodes (TE) tested were Pt, Ni, Cu and Au. The elemental composition and microstructure of the samples were characterized by means of elastic recoil detection analysis (ERD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray reflectivity (XRR).Electrical measurement of the WOx-based memory elements revealed bipolar and unipolar switching and this depended upon the oxidation conditions and TE selected. Indeed, switching events were observed in WOx samples obtained either at 450 °C or 500 °C in time windows of 180-200 s and 30-60 s, respectively. Pt and Au TE promoted bipolar switching while unipolar behavior was observed with Ni TE only; no switching events were observed with Cu TE. Good switching characteristics seems not related to the overall thickness, crystallinity and composition of the oxide, but on the W6+/W5+ ratio present on the WOx surface, surface in contact with the TE material. Interestingly, W6+/W5+ ratio can be tuned through the oxidation conditions, showing a path for optimizing the properties of the WOx-based ReRAM cells.


2014 ◽  
Vol 609-610 ◽  
pp. 565-570 ◽  
Author(s):  
Hong Xia Li ◽  
Dong Dong Shen ◽  
Wei Qing Ke ◽  
Jun Hua Xi ◽  
Zhe Kong ◽  
...  

In this paper, ZnO thin films were prepared on ITO conductive glass by direct current magnetron sputtering and the Cu electrodes were evaporated on ZnO/ITO by electric beam evaporation to get transparent Cu/ZnO/ITO resistive random access memory. The crystal structure and surface morphology were investigated by X-ray diffraction and atomic force microscopy, respectively. The transmittance spectra of ZnO/ITO in the visible region were measured by UV-VIS spectroscopy. The resistive switching characteristics of the fabricated devices were investigated by the voltage sweeping method, which showed that the transparent Cu/ZnO/ITO device had good resistive switching characteristics.


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