scholarly journals Improving Characteristic Parameters of Memristor Based on HfO2 Active Layer

2021 ◽  
Vol 906 (1) ◽  
pp. 012018
Author(s):  
Z. Kushitashvili ◽  
A. Bibilashvili
Keyword(s):  
Active Layer ◽  
Transition Metal Oxides ◽  
Memory Storage ◽  
Storage Device ◽  
Characteristic Parameters ◽  
Leakage Currents ◽  
Ideal Case ◽  
Electrical Insulator ◽  
Active Layers ◽  
Research Outcomes

Abstract The improvement of the characteristic parameters of the memristor depends on the factors such as thickness and surface area of the active layer. These parameters define leakage currents, which is the main disatvantige of the memory storage device and to improve the electrical features the leakage currents must be dropped to the zero in ideal case. In the presented work is described the electrical isolation of the active layer from the substrate by the thin layer of photoresist, which is an electrical insulator. For reducing area was used the new fotomask, which is able to reduce area 100 times. The memristor structures are designed in the form of “crossbars”, which allows us to individually investigate each memristor and create a database with the possibility of incorporating it into the microchip in the future. In this work is presented also research outcomes regarding to selection memristor’s contacts and active layers. As contacts are overviewed tungsten (W), titanium nitride (TiN) and aluminum (Al). Is considered metal and transition metal oxides as active layers WOx, HfO2, WOx +HfO2, HfO2 + HfOx. The oxide electrical and structural properties is defined from I-V, C-V, XRD and XPS characteristics.

scholarly journals Implications of NVM Based Storage on Memory Subsystem Management

2020 ◽  
Vol 10 (3) ◽  
pp. 999
Author(s):  
Hyokyung Bahn ◽  
Kyungwoon Cho
Keyword(s):  
Random Access ◽  
Disk Drive ◽  
Main Memory ◽  
Memory Storage ◽  
Storage Device ◽  
Storage Devices ◽  
Large Memory ◽  
Memory Subsystems ◽  
Non Volatile Memory ◽  
Management Techniques

Recently, non-volatile memory (NVM) has advanced as a fast storage medium, and legacy memory subsystems optimized for DRAM (dynamic random access memory) and HDD (hard disk drive) hierarchies need to be revisited. In this article, we explore the memory subsystems that use NVM as an underlying storage device and discuss the challenges and implications of such systems. As storage performance becomes close to DRAM performance, existing memory configurations and I/O (input/output) mechanisms should be reassessed. This article explores the performance of systems with NVM based storage emulated by the RAMDisk under various configurations. Through our measurement study, we make the following findings. (1) We can decrease the main memory size without performance penalties when NVM storage is adopted instead of HDD. (2) For buffer caching to be effective, judicious management techniques like admission control are necessary. (3) Prefetching is not effective in NVM storage. (4) The effect of synchronous I/O and direct I/O in NVM storage is less significant than that in HDD storage. (5) Performance degradation due to the contention of multi-threads is less severe in NVM based storage than in HDD. Based on these observations, we discuss a new PC configuration consisting of small memory and fast storage in comparison with a traditional PC consisting of large memory and slow storage. We show that this new memory-storage configuration can be an alternative solution for ever-growing memory demands and the limited density of DRAM memory. We anticipate that our results will provide directions in system software development in the presence of ever-faster storage devices.

Vertically Optimized Phase Separation with Improved Exciton Diffusion Enables High-Efficiency Organic Solar Cells with Thick Active Layers

2021 ◽  
Author(s):  
Yanming Sun ◽  
Yunhao Cai ◽  
Qian Li ◽  
Guanyu Lu ◽  
Hwa Sook Ryu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Phase Separation ◽  
Active Layer ◽  
Organic Solar Cells ◽  
High Efficiency ◽  
Diffusion Length ◽  
Active Layer Thickness ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length ◽  
Active Layers

Abstract The development of high-performance organic solar cells (OSCs) with thick active layers is of crucial importance for the roll-to-roll printing of large-area solar panels. Unfortunately, increasing the active layer thickness usually results in a significant reduction in efficiency. Herein, we fabricated efficient thick-film OSCs with an active layer consisting of one polymer donor and two non-fullerene acceptors. The two acceptors were found to possess enlarged exciton diffusion length in the mixed phase, which is beneficial to exciton generation and dissociation. Additionally, layer by layer approach was employed to optimize the vertical phase separation. Benefiting from the synergetic effects of enlarged exciton diffusion length and graded vertical phase separation, a record high efficiency of 17.31% (certified value of 16.9%) was obtained for the 300 nm-thick OSC, with an unprecedented short-circuit current density of 28.36 mA cm−2, and a high fill factor of 73.0%. Moreover, the device with an active layer thickness of 500 nm also shows a record efficiency of 15.21%. This work provides new insights into the fabrication of high-efficiency OSCs with thick active layers.

Molecular Ion S2+ and SiFn+ implantations into GaAs

1989 ◽  
Vol 147 ◽  
Author(s):  
W. D. Fan ◽  
W. Y. Wang
Keyword(s):  
Carrier Concentration ◽  
Active Layer ◽  
Concentration Profiles ◽  
Carrier Distribution ◽  
Furnace Annealing ◽  
Molecular Ion ◽  
Pl Spectra ◽  
Active Layers ◽  
Activation Efficiency

AbstractMolecular ion S2+ and SiFn+ implantations into GaAs have been investigated to form very thin active layers. After implantation, the transient annealing (TA) and furnace annealing (FA) were used. The measurements of activation efficiency, mobility, carrier concentration profiles and PL spectra were carried out. The experiments show that after TA, the activation efficiency, mobility and carrier distribution are almost the same between samples implanted with S+ at an energy of 50KeV to a dose of 3×1013cm−2 and S+2 at 100KeV to 1.5×1013cm−2. It shows that the damage of S2-implanted samples can be removed by TA, and a very thin active layer can be formed by the implantation of S2+ at 50KeV. For SiFn-implanted samples, the activation efficiency and mobility. decrease with increase of the implanted ion mass. As+ co-implantation into SiF-implanted samples has been used to improve both activation efficiency and mobility. After comparison with the properties of the SiFt implantation, S2+implantation is more acceptable to form thin active layers.

Enhancement of Organic Solar Cell Performance by Utilizing Cupper Phthalocyanine

2020 ◽  
Vol 17 (1) ◽  
pp. 1-5
Author(s):  
Shatha A. Aldaghfag
Keyword(s):  
Solar Cells ◽  
Active Layer ◽  
Conversion Efficiency ◽  
Solar Cell Performance ◽  
Active Layers ◽  
Atomic Force ◽  
Vis Spectroscopy ◽  
Evaporation Technique ◽  
Optical Variation ◽  
Photoelectrical Conversion Efficiency

An approach for improving the photoelectrical conversion efficiency of hetero-junction solar cells based on lead phthalocyanine, by incorporating cupper phthalocyanine with co-evaporation technique into the active layer has been reported in this work, the effect of adding cupper phthalocyanine (CuPc) have been studied. The morphological, optical, and electrical properties of PbPc active layer and blend have been reported. Atomic force microscope study shows a change in the roughness, UV-VIS Spectroscopy revealed that the absorbance of PbPc films increases in the blend case and has a main Q-band at wavelength 748 nm and the electrical study showed a change in (I–V) characteristics, the photoelectrical conversion efficiency (PCE) of solar cells increases. The photovoltaic parameters are discussed based on the morphology and optical variation of the active layers.

scholarly journals Effects of Organic Solvents for Composite Active Layer of PCDTBT/PC71BM on Characteristics of Organic Solar Cell Devices

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Paik-Kyun Shin ◽  
Palanisamy Kumar ◽  
Abhirami Kumar ◽  
Santhakumar Kannappan ◽  
Shizuyasu Ochiai
Keyword(s):  
Solar Cell ◽  
Organic Solvent ◽  
Organic Solvents ◽  
Active Layer ◽  
Organic Solar Cell ◽  
Bulk Heterojunction ◽  
Mixed Solution ◽  
Blend Ratio ◽  
Active Layers ◽  
Blend Ratios

Bulk heterojunction (BHJ) structure based active layers of PCDTBT/PC71BM were prepared by using different organic solvents for fabrication of organic solar cell (OSC) devices. Mixture of precursor solutions of PCDTBT/PC71BM in three different organic solvents was prepared to fabricate composite active layers by spin-coating process: chloroform; chlorobenzene; o-dichlorobenzene. Four different blend ratios (1 : 3–1 : 6) of PCDTBT: PC71BM were adopted for each organic solvent to clarify the effect on the resulting OSC device characteristics. Surface morphology of the active layers was distinctively affected by the blend ratio of PCDTBT/PC71BM in organic solvents. Influence of the blend ratio of PCDTBT/PC71BM on the OSC device parameters was discussed. Performance parameters of the resulting OSC devices with different composite active layers were comparatively investigated. Appropriate blend ratio and organic solvent to achieve better OSC device performance were proposed. Furthermore, from the UV-Vis spectrum of each active layer prepared using the PCDTBT/PC71BM mixed solution dissolved with different organic solvents, a possibility that the nanophase separation structure inside their active layer could appear was suggested.

scholarly journals Permafrost seasonal surface changes revealed from Sentinel-1 InSAR time-series, Yamal peninsula

2020 ◽  
Vol 382 ◽  
pp. 183-187
Author(s):  
Kanayim Teshebaeva ◽  
Ko J. van Huissteden ◽  
Alexander V. Puzanov ◽  
Dmitry N. Balykin ◽  
Anton I. Sinitsky ◽  
...  
Keyword(s):  
Time Series ◽  
Active Layer ◽  
Global Climate ◽  
Yamal Peninsula ◽  
Active Layers ◽  
Eurasian Continent ◽  
Time Period ◽  
Sar Imagery ◽  
Displacement Patterns ◽  
Surface Changes

Abstract. Widespread thawing of permafrost in the northern Eurasian continent causes severe problems for infrastructure and global climate. We test the potential of Sentinel-1 SAR imagery to enhance detection of permafrost surface changes in the Siberian lowlands of the northern Eurasian continent at the Yamal peninsula site. We used InSAR time-series technique to detect seasonal surface movements related to permafrost active layer changes. The satellite InSAR time-series analysis has detected continuous movements, subsidence in three zones, which have occurred during the time period from 2017 to 2018. Observed subsidence zones show up to 180 mm yr−1 rates of seasonal active layers changes. These seasonal ground displacement patterns align well with lithology and linked to anthropogenic impact on the permafrost surface changes in the area. The results show that Sentinel-1 mission is of great importance for the longer-term monitoring of active layer thickening in permafrost regions. The combined analyses of the obtained InSAR time series with additional field observations may support regular process monitoring as part of a global warming risk assessment.

Internal nanoscale architecture and charge carrier dynamics of wide bandgap non-fullerene bulk heterojunction active layers in organic solar cells

2020 ◽  
Vol 8 (44) ◽  
pp. 23628-23636
Author(s):  
Xinyu Jiang ◽  
Hongwon Kim ◽  
Peter S. Deimel ◽  
Wei Chen ◽  
Wei Cao ◽  
...  
Keyword(s):  
Solar Cells ◽  
Charge Carrier ◽  
Active Layer ◽  
Organic Solar Cells ◽  
Bulk Heterojunction ◽  
Wide Bandgap ◽  
Carrier Dynamics ◽  
Charge Carrier Dynamics ◽  
Active Layers ◽  
Solvent Additive

The nanoscale architecture of active layer based on wide bandgap non-fullerene solar cells exhibits pronounced influence by the solvent additive.

Improvement of Indirect X-ray Detector Performance by Applying Additive Solvent to the Organic Active-Layer

2021 ◽  
Vol 21 (5) ◽  
pp. 2998-3003
Author(s):  
Jongkyu Won ◽  
Hailiang Liu ◽  
Jungwon Kang
Keyword(s):  
Active Layer ◽  
Mixing Condition ◽  
Detector Performance ◽  
X Ray ◽  
Active Layers ◽  
Layer Solution

In this paper, we studied how the sensitivity of an indirect X-ray detector was changed by adding the additive solvent DIO to the organic active-layers, such as P3HT:PCBM and PBDB-T:PCBM. The crystallinity and absorbance of the active-layer films were compared with different additive DIO contents. In both active-layers, the highest crystallinity and absorbance were obtained when 3 v% of the DIO was mixed with the active-layer solution. At the same mixing condition of the DIO, the highest sensitivity, of 1.17 mA/Gy · cm2, was obtained for the P3HT:PCBM detector, and the highest sensitivity, 1.87 mA/Gy · cm2, was obtained for the PBDB-T:PCBM detector. Compared to the detector without the DIO, the sensitivities of the detectors with the P3HT:PCBM and PBDB-T:PCBM increased by 18.12% and 20.27%, respectively.

NUMERICAL SIMULATION OF OPTICAL CONFINEMENT IN ZnO BASED HETEROSTRUCTURES AT 375-NANOMETER WAVELENGTH

2008 ◽  
Vol 22 (12) ◽  
pp. 1985-1995 ◽  
Author(s):  
M. P. BHOLE ◽  
E. P. SAMUEL ◽  
D. S. PATIL
Keyword(s):  
Numerical Simulation ◽  
Layer Thickness ◽  
Mole Fraction ◽  
Active Layer ◽  
Active Layer Thickness ◽  
Optical Confinement ◽  
Double Heterostructure ◽  
Active Layers ◽  
Junction Plane ◽  
Different Thickness

Numerical simulation of optical confinement in simple double heterostructure of ZnO / Mg x Zn 1-x O and hybrid double heterostructure of Al x Ga 1-x N/ZnO have been carried out at 375 nanometer wavelength using MATLAB. Field distribution along the junction plane has been studied as a function of mole fractions of Mg and Al for different thickness of active layers. The spread of field has been estimated as a function of mole fractions and articulated as Full Width at Half Maximum (FWHM). It was found to be decreasing nonlinearly with increase of Mg mole fraction in simple heterostructure and increasing in a nonlinear manner with increase of Al mole fraction in hybrid heterostructure. FWHM deduced from our analysis was 0.265 micron for 9% and 0.16 micron for 30% Mg mole fraction. For hybrid heterostructure, FWHM values estimated were 0.13 micron and 0.1475 micron for corresponding Al mole fraction values of 9% and 30%, respectively. The narrower confinement of field intensity around the center of the active layer for the higher values of Mg mole fraction has been attributed to an increase of refractive index step between active and barrier layers. The confinement factor as a function of mole fractions and active layer thickness has been explored, and it was found to be increasing with active layer thickness. Our analysis explores the optical confinement of mode 0 in simple and hybrid heterostructures of ZnO .

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