scholarly journals Investigation of ZnO-decorated CNTs for UV Light Detection Applications

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1099 ◽  
Author(s):  
Boscarino ◽  
Filice ◽  
Sciuto ◽  
Libertino ◽  
Scuderi ◽  
...  
Keyword(s):  
Strong Interaction ◽  
Large Scale ◽  
Room Temperature ◽  
Low Voltage ◽  
Uv Light ◽  
Electrical Response ◽  
Dense Layer ◽  
Zno Nanoparticle ◽  
Zno Nps ◽  
Operational Conditions

Multi-walled carbon nanotubes (CNTs) decorated with zinc oxide nanoparticles (ZnO NPs) were prepared in isopropanol solution by a simple, room-temperature process and characterized from structural, morphological, electronic, and optical points of view. A strong interaction between ZnO and CNTs is fully confirmed by all the characterization techniques. ZnO-CNTs nanocomposites, with different weight ratios, were deposited as a dense layer between two electrodes, in order to investigate the electrical behaviour. In particular, the electrical response of the nanocomposite layers to UV light irradiation was recorded for a fixed voltage: As the device is exposed to the UV lamp, a sharp current drop takes place and then an increase is observed as the irradiation is stopped. The effect can be explained by adsorption and desorption phenomena taking place on the ZnO nanoparticle surface under irradiation and by charge transfer between ZnO and CNTs, thanks to the strong interaction between the two nanomaterials. The nanocomposite material shows good sensitivity and fast response to UV irradiation. Room temperature and low-cost processes used for the device preparation combined with room temperature and low voltage operational conditions make this methodology very promising for large scale UV detectors applications.

Ultraviolet Sensor Based on Organic/Inorganic Heterojunction between PEDOT:PSS and ZnO Nanoparticles Thin Films

2015 ◽  
Vol 1131 ◽  
pp. 157-162 ◽  
Author(s):  
Kittipong Tantisantisom ◽  
Kanpitcha Jiramitmonkon ◽  
Thanakorn Jiemsakul ◽  
Thanawee Chodjarusawad ◽  
Udom Asawapirom
Keyword(s):  
Indium Tin Oxide ◽  
Uv Light ◽  
Electrical Response ◽  
Forward Bias ◽  
Dark Field ◽  
Bias Current ◽  
Emission Model ◽  
Uv Detector ◽  
Zno Nps ◽  
Current Voltage

In this work, the ultraviolet (UV) sensors based on heterojunction between layer of zinc oxide nanoparticles (ZnO NPs) and poly (3,4-ethylenedioxythiophene):poly (styrenesulfonic acid) (PEDOT:PSS) were fabricated, characterized and studied in the electrical response to UV 365 nm. The ZnO NPs layer was solution-based coated on the top of PEDOT:PSS film on the patterned indium tin oxide (ITO) coated on glass. Aluminum was deposited as the top electrode of the device. The current-voltage (I-V) characteristic shows the rectifying behavior in the dark field. With the UV irradiation, the reverse bias current can be found and the forward bias current also highly increases. The current-voltage data fitting with the thermionic emission model shows that the potential barrier height at the heterojunction decreases with illuminating by UV light. Relative high photoresponse of the device exhibits the potential to UV detector application.

Room-Temperature ZnO Nanoparticle Ethanol Gas Sensors under UV Illumination

2012 ◽  
Vol 486 ◽  
pp. 39-43 ◽  
Author(s):  
S.P. Chang
Keyword(s):  
Gas Sensor ◽  
Gas Sensors ◽  
Spin Coating ◽  
Room Temperature ◽  
Uv Light ◽  
Light Illumination ◽  
Zno Nanoparticle ◽  
Uv Illumination ◽  
Potential Applications ◽  
Nanoparticle Film

A zinc oxide (ZnO) nanoparticle gas sensor was formed by spin coating. We annealed the film at 400, 600, and 800°C for 1 h in air to create a gas sensor. The responses of the gas sensor to ethanol under UV light illumination were investigated. We found that the ZnO nanoparticle film annealed at 800°C had the highest sensitivity. This can be attributed to the fact that the defects of ZnO nanoparticle film annealed at 800°C are considerably more than those for the film annealed at other temperatures. This study demonstrates that ZnO nanoparticles have potential applications as room-temperature ethanol sensors.

scholarly journals UV Illumination Room-Temperature ZnO Nanoparticle Ethanol Gas Sensors

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Sheng-Po Chang ◽  
Kuan-Yu Chen
Keyword(s):  
Gas Sensor ◽  
Gas Sensors ◽  
Room Temperature ◽  
Uv Light ◽  
Light Illumination ◽  
Zno Nanoparticle ◽  
Uv Illumination ◽  
Potential Applications ◽  
Film Annealing ◽  
Nanoparticle Film

Zinc oxide (ZnO) nanoparticle gas sensor was formed by spin coating. We annealed the film at 400, 600, and 800°C for 1 hour in air to make gas sensor. The responses of gas sensor to ethanol with UV light illumination were investigated. It could be observed that the ZnO nanoparticle film annealing at 800°C has the highest sensitivity. It can be attributed to the defects of ZnO nanoparticle film annealing at 800°C much more than other annealing temperatures. The study shows that the ZnO nanoparticles have potential applications as RT ethanol sensors.

scholarly journals Characterisation of a new generation of VUV low-light sensors

2020 ◽  
Vol 227 ◽  
pp. 02002
Author(s):  
G. Gallina ◽  
F Retière
Keyword(s):  
Large Scale ◽  
Low Voltage ◽  
Detection System ◽  
Ultra Violet ◽  
High Gain ◽  
Scintillation Light ◽  
Operational Conditions ◽  
Photo Sensor ◽  
Enriched Xenon Observatory ◽  
New Generation

Silicon Photo-Multipliers (SiPMs) have emerged as a compelling photo-sensor solution over the course of the last decade. In contrast to the widely used Photomultiplier Tubes (PMTs), SiPMs are low-voltage powered, optimal for operation at cryogenic temperatures, and have low radioactivity lev- els with high gain stability over the time in operational conditions. For these reasons, large-scale low-background cryogenic experiments, such as the next- generation Enriched Xenon Observatory experiment (nEXO), are migrating to a SiPM-based light detection system. In this paper we report on the charac- terization of the Hamamatsu VUV4 (S/N: S13370-6152) Vacuum Ultra-Violet (VUV) sensitive Multi-Pixel Photon Counters (MPPC)s as part of the develop- ment of a solution for the detection of liquid xenon scintillation light for the nEXO experiment.

Conformation and electronic structure of aromatic chloroformates

1987 ◽  
Vol 52 (4) ◽  
pp. 970-979 ◽  
Author(s):  
Otto Exner ◽  
Pavel Fiedler
Keyword(s):  
Electronic Structure ◽  
Oxygen Atom ◽  
Strong Interaction ◽  
Electron Distribution ◽  
Room Temperature ◽  
Functional Group ◽  
Dipole Moments ◽  
Carbonyl Oxygen ◽  
Nonpolar Solvents ◽  
Single Method

Aromatic chloroformates Ib-Ie were shown to exist in the ap conformation, in agreement with aliphatic chloroformates, i.e. the alkyl group is situated cis to the carbonyl oxygen atom as it is the case in all esters. While 4-nitrophenyl chloroformate (Ie) is in this conformation in crystal, in solution at most several tenths of percent of the sp conformation may be populated at room temperature and in nonpolar solvents only. A new analysis of dipole moments explained the previous puzzling results and demonstrated the impossibility to determine the conformation by this single method, in consequence of the strong interaction of adjoining bonds. If, however, the ap conformation is once proven, the dipole moments reveal some features of the electron distribution on the functional group, characterized by the enhanced polarity of the C-Cl bond and reduced polarity of the C=O bond. This is in agreement with the observed bond lengths and angles.

In-situ construction of direct Z-scheme AgBr/α-Ag2WO4 heterojunction with promoted spatial charge migration and photocatalytic performance

2021 ◽  
Author(s):  
Xiao-Ya Zhai ◽  
Yifan Zhao ◽  
Guo-Ying Zhang ◽  
Bing-Yu Wang ◽  
Qi-Yun Mao
Keyword(s):  
Anion Exchange ◽  
Large Scale ◽  
Room Temperature ◽  
Photocatalytic Performance ◽  
Charge Migration ◽  
Time Saving ◽  
Spatial Charge ◽  
Construction Strategy ◽  
Large Scale Synthesis

In the work, a direct Z-scheme AgBr/α-Ag2WO4 heterojunction was prepared by in-situ anion exchange at room temperature. The construction strategy is energy- and time-saving for large scale synthesis. The α-Ag2WO4...

COMPOSITE TRANSISTOR CELL USING DYNAMIC BODY BIAS FOR HIGH GAIN AND LOW-VOLTAGE APPLICATIONS

2014 ◽  
Vol 23 (08) ◽  
pp. 1450108 ◽  
Author(s):  
VANDANA NIRANJAN ◽  
ASHWANI KUMAR ◽  
SHAIL BALA JAIN
Keyword(s):  
Low Power ◽  
Large Scale ◽  
Low Voltage ◽  
Supply Voltage ◽  
High Gain ◽  
Signal Frequency ◽  
Output Impedance ◽  
Self Cascode ◽  
Intrinsic Gain ◽  
Body Bias

In this work, a new composite transistor cell using dynamic body bias technique is proposed. This cell is based on self cascode topology. The key attractive feature of the proposed cell is that body effect is utilized to realize asymmetric threshold voltage self cascode structure. The proposed cell has nearly four times higher output impedance than its conventional version. Dynamic body bias technique increases the intrinsic gain of the proposed cell by 11.17 dB. Analytical formulation for output impedance and intrinsic gain parameters of the proposed cell has been derived using small signal analysis. The proposed cell can operate at low power supply voltage of 1 V and consumes merely 43.1 nW. PSpice simulation results using 180 nm CMOS technology from Taiwan Semiconductor Manufacturing Company (TSMC) are included to prove the unique results. The proposed cell could constitute an efficient analog Very Large Scale Integration (VLSI) cell library in the design of high gain analog integrated circuits and is particularly interesting for biomedical and instrumentation applications requiring low-voltage low-power operation capability where the processing signal frequency is very low.

scholarly journals A Survey on Edge Performance Benchmarking

2021 ◽  
Vol 54 (3) ◽  
pp. 1-33
Author(s):  
Blesson Varghese ◽  
Nan Wang ◽  
David Bermbach ◽  
Cheol-Ho Hong ◽  
Eyal De Lara ◽  
...  
Keyword(s):  
Large Scale ◽  
Future Internet ◽  
Coupled Systems ◽  
Operational Conditions ◽  
Loosely Coupled ◽  
Performance Benchmarking ◽  
The Past ◽  
Geographically Dispersed ◽  
Tightly Coupled ◽  
History Of

Edge computing is the next Internet frontier that will leverage computing resources located near users, sensors, and data stores to provide more responsive services. Therefore, it is envisioned that a large-scale, geographically dispersed, and resource-rich distributed system will emerge and play a key role in the future Internet. However, given the loosely coupled nature of such complex systems, their operational conditions are expected to change significantly over time. In this context, the performance characteristics of such systems will need to be captured rapidly, which is referred to as performance benchmarking, for application deployment, resource orchestration, and adaptive decision-making. Edge performance benchmarking is a nascent research avenue that has started gaining momentum over the past five years. This article first reviews articles published over the past three decades to trace the history of performance benchmarking from tightly coupled to loosely coupled systems. It then systematically classifies previous research to identify the system under test, techniques analyzed, and benchmark runtime in edge performance benchmarking.

scholarly journals Graphene-Based Artificial Synapses with Tunable Plasticity

2021 ◽  
Vol 17 (4) ◽  
pp. 1-21
Author(s):  
He Wang ◽  
Nicoleta Cucu Laurenciu ◽  
Yande Jiang ◽  
Sorin Cotofana
Keyword(s):  
Synaptic Plasticity ◽  
Weight Change ◽  
Time Scale ◽  
Large Scale ◽  
Synaptic Weight ◽  
Low Voltage ◽  
Logic Gates ◽  
Full Potential ◽  
Back Gate ◽  
Input Spike

Design and implementation of artificial neuromorphic systems able to provide brain akin computation and/or bio-compatible interfacing ability are crucial for understanding the human brain’s complex functionality and unleashing brain-inspired computation’s full potential. To this end, the realization of energy-efficient, low-area, and bio-compatible artificial synapses, which sustain the signal transmission between neurons, is of particular interest for any large-scale neuromorphic system. Graphene is a prime candidate material with excellent electronic properties, atomic dimensions, and low-energy envelope perspectives, which was already proven effective for logic gates implementations. Furthermore, distinct from any other materials used in current artificial synapse implementations, graphene is biocompatible, which offers perspectives for neural interfaces. In view of this, we investigate the feasibility of graphene-based synapses to emulate various synaptic plasticity behaviors and look into their potential area and energy consumption for large-scale implementations. In this article, we propose a generic graphene-based synapse structure, which can emulate the fundamental synaptic functionalities, i.e., Spike-Timing-Dependent Plasticity (STDP) and Long-Term Plasticity . Additionally, the graphene synapse is programable by means of back-gate bias voltage and can exhibit both excitatory or inhibitory behavior. We investigate its capability to obtain different potentiation/depression time scale for STDP with identical synaptic weight change amplitude when the input spike duration varies. Our simulation results, for various synaptic plasticities, indicate that a maximum 30% synaptic weight change and potentiation/depression time scale range from [-1.5 ms, 1.1 ms to [-32.2 ms, 24.1 ms] are achievable. We further explore the effect of our proposal at the Spiking Neural Network (SNN) level by performing NEST-based simulations of a small SNN implemented with 5 leaky-integrate-and-fire neurons connected via graphene-based synapses. Our experiments indicate that the number of SNN firing events exhibits a strong connection with the synaptic plasticity type, and monotonously varies with respect to the input spike frequency. Moreover, for graphene-based Hebbian STDP and spike duration of 20ms we obtain an SNN behavior relatively similar with the one provided by the same SNN with biological STDP. The proposed graphene-based synapse requires a small area (max. 30 nm 2 ), operates at low voltage (200 mV), and can emulate various plasticity types, which makes it an outstanding candidate for implementing large-scale brain-inspired computation systems.

scholarly journals Zirconium-Doped Chromium IV Oxide Nanocomposites: Synthesis, Characterization, and Photocatalysis towards the Degradation of Organic Dyes

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 117
Author(s):  
Zahir Muhammad ◽  
Farman Ali ◽  
Muhammad Sajjad ◽  
Nisar Ali ◽  
Muhammad Bilal ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Solid State ◽  
Room Temperature ◽  
Organic Dyes ◽  
Uv Light ◽  
Heterogeneous Photocatalysis ◽  
Ft Ir ◽  
Complete Mineralization

Degradation of organic dyes and their byproducts by heterogeneous photocatalysts is an essential process, as these dyes can be potentially discharged in wastewater and threaten aquatic and xerophyte life. Therefore, their complete mineralization into nontoxic components (water and salt) is necessary through the process of heterogeneous photocatalysis. In this study, Zr/CrO2 (Zirconium-doped chromium IV oxide) nanocomposite-based photocatalysts with different compositions (1, 3, 5, 7 & 9 wt.%) were prepared by an environmentally friendly, solid-state reaction at room temperature. The as-prepared samples were calcined under air at 450 °C in a furnace for a specific period of time. The synthesis of Zr/CrO2 photocatalysts was confirmed by various techniques, including XRD, SEM, EDX, FT-IR, UV-Vis, and BET. The photocatalytic properties of all samples were tested towards the degradation of methylene blue and methyl orange organic dyes under UV light. The results revealed a concentration-dependent photocatalytic activity of photocatalysts, which increased the amount of dopant (up to 5 wt.%). However, the degradation efficiency of the catalysts decreased upon further increasing the amount of dopant due to the recombination of holes and photoexcited electrons.

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