scholarly journals Fabrication of Porous Silicon Based Humidity Sensing Elements on Paper

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Tero Jalkanen ◽  
Anni Määttänen ◽  
Ermei Mäkilä ◽  
Jaani Tuura ◽  
Martti Kaasalainen ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Smart Cities ◽  
Low Cost ◽  
Electrical Characterization ◽  
Fabrication Process ◽  
Sensing Element ◽  
Paper Substrate ◽  
Roll To Roll ◽  
Silver Electrodes ◽  
Silicon Based

A roll-to-roll compatible fabrication process of porous silicon (pSi) based sensing elements for a real-time humidity monitoring is described. The sensing elements, consisting of printed interdigitated silver electrodes and a spray-coated pSi layer, were fabricated on a coated paper substrate by a two-step process. Capacitive and resistive responses of the sensing elements were examined under different concentrations of humidity. More than a three orders of magnitude reproducible decrease in resistance was measured when the relative humidity (RH) was increased from 0% to 90%. A relatively fast recovery without the need of any refreshing methods was observed with a change in RH. Humidity background signal and hysteresis arising from the paper substrate were dependent on the thickness of sensing pSi layer. Hysteresis in most optimal sensing element setup (a thick pSi layer) was still noticeable but not detrimental for the sensing. In addition to electrical characterization of sensing elements, thermal degradation and moisture adsorption properties of the paper substrate were examined in connection to the fabrication process of the silver electrodes and the moisture sensitivity of the paper. The results pave the way towards the development of low-cost humidity sensors which could be utilized, for example, in smart packaging applications or in smart cities to monitor the environment.

scholarly journals Synaptic and Fast Switching Memristance in Porous Silicon-Based Structures

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 825 ◽  
Author(s):  
Vicente Torres-Costa ◽  
Ermei Mäkilä ◽  
Sari Granroth ◽  
Edwin Kukk ◽  
Jarno Salonen
Keyword(s):  
Porous Silicon ◽  
Low Cost ◽  
Electrical Characterization ◽  
Cost Effective ◽  
Successful Implementation ◽  
Memristive Behavior ◽  
Silicon Structures ◽  
Proper Material ◽  
Silicon Based ◽  
New Generation

Memristors are two terminal electronic components whose conductance depends on the amount of charge that has flown across them over time. This dependence can be gradual, such as in synaptic memristors, or abrupt, as in resistive switching memristors. Either of these memory effects are very promising for the development of a whole new generation of electronic devices. For the successful implementation of practical memristors, however, the development of low cost industry compatible memristive materials is required. Here the memristive properties of differently processed porous silicon structures are presented, which are suitable for different applications. Electrical characterization and SPICE simulations show that laser-carbonized porous silicon shows a strong synaptic memristive behavior influenced by defect diffusion, while wet-oxidized porous silicon has strong resistance switching properties, with switching ratios over 8000. Results show that practical memristors of either type can be achieved with porous silicon whose memristive properties can be adjusted by the proper material processing. Thus, porous silicon may play an important role for the successful realization of practical memristorics with cost-effective materials and processes.

A novel, nanocrystal (nc) based non-volatile memory device

2000 ◽  
Vol 638 ◽  
Author(s):  
Jan W. De Blauwe ◽  
Marty L. Green ◽  
Tom W. Sorsch ◽  
Garry R. Weber ◽  
Jeff D. Bude ◽  
...  
Keyword(s):  
Low Cost ◽  
Electrical Characterization ◽  
Memory Device ◽  
Fabrication Process ◽  
Floating Gate ◽  
Potential Candidate ◽  
Non Volatile Memory ◽  
Volatile Memory

AbstractThis paper describes the fabrication, and structural and electrical characterization of a new, aerosol-nanocrystal floating-gate FET, aimed at non-volatile memory (NVM) applications. This aerosol- nanocrystal NVM device features program/erase characteristics comparable to conventional stacked gate NVM devices, excellent endurance (>105 P/E cycles), and long-term non-volatility in spite of a thin bottom oxide (55-60Å). In addition, a very simple fabrication process makes this aerosol-nanocrystal NVM device a potential candidate for low cost NVM applications.

scholarly journals Design & Development of Laser Etched Porous-Silicon Capacitive Chip for Rapid Sensing of Pesticide Solvents

2021 ◽  
Author(s):  
shailesh mahendralal gheewala ◽  
Chinthakunta Parmesh ◽  
Piyush N. Patel ◽  
Rasika Dhavse
Keyword(s):  
Porous Silicon ◽  
Organic Solvents ◽  
Optical Sensors ◽  
Limit Of Detection ◽  
Low Cost ◽  
Single Layer ◽  
Capacitive Sensor ◽  
Average Pore ◽  
Chip Design ◽  
Silicon Based

Abstract This work presents the development of porous silicon-based electrical sensor for the detection and quantification of organic solvents. The design of silicon chip is modeled as capacitive sensor. Different electrode configurations like coplanar top electrodes, top-bottom, coplanar bottom electrodes were analyzed in order to select optimum chip design for sensing application. The prototype chip was fabrication that used a mechanized pulse fiber laser etching process in order to develop a single-layer silicon structure with uniform porous structures. The fabricated chip was characterized using scanning electron microscopy and it shows an average pore diameter of 55.22 µm and pore depth of 98.9 µm. Organic solvents like ethanol, methanol, acetonitrile were tested and analyzed in order to investigate the performance of the proposed chip. Unlike porous silicon based optical sensors, the proposed sensor exhibited stable results up to 35 days at room temperature. The application of the proposed sensor chip is demonstrated for sensing and for the quantification of Atrazine chemical which is a pesticide solvent which is utilized in farming to control weeds. The sensitivity and the limit of detection was found to be 0.51 nF/ppm and 0.929 ppm respectively. The proposed capacitive-based porous silicon chip is suitable for time-effective and low-cost sensing and detection of organic solvents that are used in food industry.

Oxidized Porous Silicon Moisture Sensors for Evaluation of Microelectronic Packaging

1991 ◽  
Vol 225 ◽  
Author(s):  
M. J. Kelly ◽  
T. R. Guilinger ◽  
D. W. Peterson ◽  
M. R. Tuck ◽  
J. N. Sweet
Keyword(s):  
Porous Silicon ◽  
Integrated Circuits ◽  
Sensing Element ◽  
Oxidation Treatment ◽  
Moisture Barrier ◽  
Barrier Coating ◽  
Oxidized Porous Silicon ◽  
Consistent Performance ◽  
Silicon Based ◽  
Intentional Introduction

ABSTRACTAccurate moisture measurements in microelectronic assemblies are crucial in assessing reliability of integrated circuits (ICs). We describe the fabrication and use of a silicon-based device for evaluation of moisture barrier coatings. The capacitive moisture sensors use oxidized porous silicon (OPS) as the sensing element. Porous silicon (PS) is formed by anodization of Si in hydrofluoric acid (HF). Oxidation of PS in oxygen produces OPS, which is also porous if an appropriate starting microstructure and oxidation treatment are selected. Metallization layers on the OPS and the wafer back complete the capacitor structure. The capacitance of OPS sensors is functionally related to the moisture content of the surrounding atmosphere. For example, the capacitance of one sensor changed from 4 nF/cm2when exposed to a moisture level of 300 ppm by volume (ppmv) to 36 nF/cm2at 10,000 ppmv. In addition to this excellent sensitivity, capacitor response to step changes in moisture is rapid and reversible. The sensors are also rugged, as demonstrated by their consistent performance during accelerated testing at 85% relative humidity and 140°C. A silicon nitride IC moisture barrier coating was deposited on sensors of this type after normal ceramic dual in-line packaging. Sensor operability after coating deposition was confirmed following intentional introduction of a pinhole into the moisture barrier coating.

scholarly journals Virtualizing AI at the Distributed Edge Towards Intelligent IoT Applications

2021 ◽  
Vol 10 (1) ◽  
pp. 13
Author(s):  
Claudia Campolo ◽  
Giacomo Genovese ◽  
Antonio Iera ◽  
Antonella Molinaro
Keyword(s):  
Resource Constraints ◽  
Smart Cities ◽  
Traditional Approach ◽  
Low Cost ◽  
Iot Applications ◽  
Software And Hardware ◽  
Iot Devices ◽  
Consumer Devices ◽  
Hardware Platforms ◽  
Smart Factories

Several Internet of Things (IoT) applications are booming which rely on advanced artificial intelligence (AI) and, in particular, machine learning (ML) algorithms to assist the users and make decisions on their behalf in a large variety of contexts, such as smart homes, smart cities, smart factories. Although the traditional approach is to deploy such compute-intensive algorithms into the centralized cloud, the recent proliferation of low-cost, AI-powered microcontrollers and consumer devices paves the way for having the intelligence pervasively spread along the cloud-to-things continuum. The take off of such a promising vision may be hurdled by the resource constraints of IoT devices and by the heterogeneity of (mostly proprietary) AI-embedded software and hardware platforms. In this paper, we propose a solution for the AI distributed deployment at the deep edge, which lays its foundation in the IoT virtualization concept. We design a virtualization layer hosted at the network edge that is in charge of the semantic description of AI-embedded IoT devices, and, hence, it can expose as well as augment their cognitive capabilities in order to feed intelligent IoT applications. The proposal has been mainly devised with the twofold aim of (i) relieving the pressure on constrained devices that are solicited by multiple parties interested in accessing their generated data and inference, and (ii) and targeting interoperability among AI-powered platforms. A Proof-of-Concept (PoC) is provided to showcase the viability and advantages of the proposed solution.

scholarly journals An IoT-Based Participatory Antitheft System for Public Safety Enhancement in Smart Cities

Smart Cities ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 919-937
Author(s):  
Nikos Papadakis ◽  
Nikos Koukoulas ◽  
Ioannis Christakis ◽  
Ilias Stavrakas ◽  
Dionisis Kandris
Keyword(s):  
Smart Cities ◽  
Low Cost ◽  
Negative Influence ◽  
Asset Tracking ◽  
Tracking Tasks ◽  
Tracking Process ◽  
The Impact ◽  
Operation Center ◽  
Safety Enhancement ◽  
Selection Of

The risk of theft of goods is certainly an important source of negative influence in human psychology. This article focuses on the development of a scheme that, despite its low cost, acts as a smart antitheft system that achieves small property detection. Specifically, an Internet of Things (IoT)-based participatory platform was developed in order to allow asset-tracking tasks to be crowd-sourced to a community. Stolen objects are traced by using a prototype Bluetooth Low Energy (BLE)-based system, which sends signals, thus becoming a beacon. Once such an item (e.g., a bicycle) is stolen, the owner informs the authorities, which, in turn, broadcast an alert signal to activate the BLE sensor. To trace the asset with the antitheft tag, participants use their GPS-enabled smart phones to scan BLE tags through a specific smartphone client application and report the location of the asset to an operation center so that owners can locate their assets. A stolen item tracking simulator was created to support and optimize the aforementioned tracking process and to produce the best possible outcome, evaluating the impact of different parameters and strategies regarding the selection of how many and which users to activate when searching for a stolen item within a given area.

scholarly journals 60–700 K CTAT and PTAT Temperature Sensors with 4H-SiC Schottky Diodes

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 942
Author(s):  
Razvan Pascu ◽  
Gheorghe Pristavu ◽  
Gheorghe Brezeanu ◽  
Florin Draghici ◽  
Philippe Godignon ◽  
...  
Keyword(s):  
Low Cost ◽  
Schottky Diodes ◽  
Schottky Contact ◽  
High Sensitivity ◽  
Xrd Analysis ◽  
Absolute Temperature ◽  
Lower Sensitivity ◽  
Readout Circuit ◽  
Sensing Element ◽  
High Performing

A SiC Schottky dual-diode temperature-sensing element, suitable for both complementary variation of VF with absolute temperature (CTAT) and differential proportional to absolute temperature (PTAT) sensors, is demonstrated over 60–700 K, currently the widest range reported. The structure’s layout places the two identical diodes in close, symmetrical proximity. A stable and high-barrier Schottky contact based on Ni, annealed at 750 °C, is used. XRD analysis evinced the even distribution of Ni2Si over the entire Schottky contact area. Forward measurements in the 60–700 K range indicate nearly identical characteristics for the dual-diodes, with only minor inhomogeneity. Our parallel diode (p-diode) model is used to parameterize experimental curves and evaluate sensing performances over this far-reaching domain. High sensitivity, upwards of 2.32 mV/K, is obtained, with satisfactory linearity (R2 reaching 99.80%) for the CTAT sensor, even down to 60 K. The PTAT differential version boasts increased linearity, up to 99.95%. The lower sensitivity is, in this case, compensated by using a high-performing, low-cost readout circuit, leading to a peak 14.91 mV/K, without influencing linearity.

Development of Bridge Tooling for Fabricating Mold Inserts of Aspheric Optical Lens

2012 ◽  
Vol 516 ◽  
pp. 228-233
Author(s):  
Chil Chyuan Kuo ◽  
Zhi Yang Lin
Keyword(s):  
Success Rate ◽  
Silicone Rubber ◽  
Low Cost ◽  
Fabrication Process ◽  
Optical Lens ◽  
Aspheric Lenses

Bridge tooling has been developed for fabricating the temporary mould inserts of aspheric lenses using silicone rubber materials. Prototype material for aspheric lenses is not recommended as quartz due to the low success rate in the fabrication process. This technology provides a fast, low cost and highly successful rate of fabricating the epoxy-based composite mould inserts of plastic aspheric optical lenses.

Integration of lateral porous silicon membranes into planar microfluidics

Lab on a Chip ◽  
2015 ◽  
Vol 15 (3) ◽  
pp. 833-838 ◽  
Author(s):  
Thierry Leïchlé ◽  
David Bourrier
Keyword(s):  
Porous Silicon ◽  
Fabrication Process ◽  
Microfluidic Channels ◽  
Dead End ◽  
Silicon Membranes ◽  
On Chip ◽  
Mesoporous Membranes

A unique fabrication process was developed to integrate lateral porous silicon membranes into planar microfluidic channels. These mesoporous membranes were demonstrated to be suitable for on-chip dead-end microfiltration.

An Investigation onto Polydimethylsiloxane (PDMS) Printing Plate of Multiple Functional Solid Line by Flexographic

2013 ◽  
Vol 844 ◽  
pp. 158-161 ◽  
Author(s):  
M.I. Maksud ◽  
Mohd Sallehuddin Yusof ◽  
M. Mahadi Abdul Jamil
Keyword(s):  
Laser Ablation ◽  
Line Width ◽  
High Speed ◽  
Printed Electronics ◽  
Low Cost ◽  
Flexible Substrates ◽  
Large Area ◽  
Printing Plate ◽  
Roll To Roll ◽  
Printing Processes

Recently low cost production is vital to produce printed electronics by roll to roll manufacturing printing process like a flexographic. Flexographic has a high speed technique which commonly used for printing onto large area flexible substrates. However, the minimum feature sizes achieved with roll to roll printing processes, such as flexographic is in the range of fifty microns. The main contribution of this limitation is photopolymer flexographic plate unable to be produced finer micron range due to film that made by Laser Ablation Mask (LAMs) technology not sufficiently robust and consequently at micron ranges line will not be formed on the printing plate. Hence, polydimethylsiloxane (PDMS) is used instead of photopolymer. Printing trial had been conducted and multiple solid lines successfully printed for below fifty microns line width with no interference between two adjacent lines of the printed images.

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