scholarly journals Utilization of Amorphous Silicon Carbide (a-Si:C:H) as a Resistive Layer in Gas Microstrip Detectors

1995 ◽  
Vol 377 ◽  
Author(s):  
W. S. Hong ◽  
H. S. Cho ◽  
V. Perez-Mendez ◽  
W. G. Gong
Keyword(s):  
Amorphous Silicon ◽  
Low Cost ◽  
Chemical Vapor ◽  
Light Sensitivity ◽  
Attractive Alternative ◽  
Large Area ◽  
Doping Density ◽  
Resistive Layer ◽  
Wide Range ◽  
Microstrip Detectors

ABSTRACTThin semiconducting films of hydrogenated amorphous silicon (a-Si:H) and its carbon alloy (a-Si:C:H) were applied to gas microstrip detectors in order to control gain instabilities due to charges on the substrate. Thin (∼100 nm) layers of a-Si:H or p-doped a-Si:C:H were placed either over or under the electrodes using the plasma enhanced chemical vapor deposition (PECVD) technique to provide the substrate with a suitable surface conductivity. By changing the carbon content and boron doping density, the sheet resistance of the a-Si:C:H coating could be successfully controlled in the range of 1012 ∼ 1017 μ/□, and the light sensitivity, which causes the resistivity to vary with ambient light conditions, was minimized. An avalanche gain of 5000 and energy resolution of 20% FWHM were achieved and the gain remained constant over a week of operation. A-Si:C:H film is an attractive alternative to ion-implanted or semiconducting glass due to the wide range of resistivities possible and the feasibility of making deposits over a large area at low cost.

Computer simulation study about the dependence of amorphous silicon photonic waveguides efficiency on the material quality

2020 ◽  
Vol 90 (3) ◽  
pp. 30502
Author(s):  
Alessandro Fantoni ◽  
João Costa ◽  
Paulo Lourenço ◽  
Manuela Vieira
Keyword(s):  
Amorphous Silicon ◽  
High Throughput Screening ◽  
Simulation Analysis ◽  
Low Cost ◽  
Deposition Process ◽  
Large Area ◽  
Sidewall Roughness ◽  
Sensing Applications ◽  
Fabrication Defects ◽  
The Impact

Amorphous silicon PECVD photonic integrated devices are promising candidates for low cost sensing applications. This manuscript reports a simulation analysis about the impact on the overall efficiency caused by the lithography imperfections in the deposition process. The tolerance to the fabrication defects of a photonic sensor based on surface plasmonic resonance is analysed. The simulations are performed with FDTD and BPM algorithms. The device is a plasmonic interferometer composed by an a-Si:H waveguide covered by a thin gold layer. The sensing analysis is performed by equally splitting the input light into two arms, allowing the sensor to be calibrated by its reference arm. Two different 1 × 2 power splitter configurations are presented: a directional coupler and a multimode interference splitter. The waveguide sidewall roughness is considered as the major negative effect caused by deposition imperfections. The simulation results show that plasmonic effects can be excited in the interferometric waveguide structure, allowing a sensing device with enough sensitivity to support the functioning of a bio sensor for high throughput screening. In addition, the good tolerance to the waveguide wall roughness, points out the PECVD deposition technique as reliable method for the overall sensor system to be produced in a low-cost system. The large area deposition of photonics structures, allowed by the PECVD method, can be explored to design a multiplexed system for analysis of multiple biomarkers to further increase the tolerance to fabrication defects.

NUMERICAL ANALYSIS OF FLOW BEHAVIOR IN GAS-LIQUID CYLINDRICAL CYCLONE (GLCC©*) SEPARATORS WITH INLET DESIGN MODIFICATIONS

2021 ◽  
pp. 1-27
Author(s):  
Srinivas Swaroop Kolla ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Numerical Study ◽  
Flow Behavior ◽  
Low Cost ◽  
Field Application ◽  
Attractive Alternative ◽  
Inlet Section ◽  
Wide Range ◽  
Cylindrical Cyclone ◽  
Light Oil ◽  
Section Design

Abstract The Gas-Liquid Cylindrical Cyclone (GLCC©*) is a simple, compact and low-cost separator, which provides an economically attractive alternative to conventional gravity-based separators over a wide range of applications. More than 6,500 GLCC©'s have been installed in the field to date around the world over the past 2 decades. The GLCC© inlet section design is a key parameter, which is crucial for its performance and proper operation. The flow behavior in the GLCC© body is highly dependent on the fluid velocities generated at the reduced area nozzle inlet. An earlier study (Kolla et al. [1]) recommended design modifications to the inlet section, based on safety and structural robustness. It is important to ensure that these proposed configuration modifications do not adversely affect the flow behavior at the inlet and the overall performance of the GLCC©. This paper presents a numerical study utilizing specific GLCC© field application working under 3 different case studies representing the flow entering the GLCC, separating light oil, steam flooded wells in Minas, Indonesia. Commercially available Computational Fluid Dynamics (CFD) software is utilized to analyze the hydrodynamics of flow with the proposed modifications of the inlet section for GLCC© field applications.

scholarly journals Reshaping Hybrid Perovskites Emission with Flexible Polymer Microcavities

2020 ◽  
Vol 230 ◽  
pp. 00006
Author(s):  
Paola Lova ◽  
Paolo Giusto ◽  
Francesco Di Stasio ◽  
Giovanni Manfredi ◽  
Giuseppe M. Paternò ◽  
...  
Keyword(s):  
Thin Films ◽  
Photonic Crystals ◽  
Low Cost ◽  
Scale Production ◽  
Large Area ◽  
Light Emitting Devices ◽  
Flexible Polymer ◽  
Hybrid Perovskite ◽  
Wide Range ◽  
Solution Processable

Thanks to versatile optoelectronic properties solution processable perovskites have attracted increasing interest as active materials in photovoltaic and light emitting devices. However, the deposition of perovskite thin films necessitates wide range solvents that are incompatible with many other solution-processable media, including polymers that are usually dissolved by the perovskite solvents. In this work, we demonstrate that hybrid perovskite thin films can be coupled with all polymer planar photonic crystals with different approaches to achieve emission intensity enhancement and reshaping using different approaches. The possibility to control and modify the emission spectrum of a solution processable perovskite via a simple spun-cast polymer structure is indeed of great interest in optoelectronic applications requiring high color purity or emission directionality. Furthermore, thanks to the ease of fabrication and scalability of solution-processed photonic crystals, this approach could enable industrial scale production of low-cost, large area, lightweight and flexible polymer-perovskite lighting devices, which may be tuned without resorting to compositional engineering.

Large-area Deposition of Amorphous Silicon Alloys Using a Roll-to-roll Operation

2005 ◽  
Vol 870 ◽  
Author(s):  
Subhendu Guha ◽  
Jeffrey Yang
Keyword(s):  
Amorphous Silicon ◽  
Triple Junction ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Chemical Vapor ◽  
Large Area ◽  
Silicon Alloys ◽  
Roll To Roll ◽  
Layer Structures ◽  
Area Deposition

AbstractLarge-area deposition of thin-film amorphous silicon alloy triple-junction solar cells on lightweight and flexible stainless steel substrate is described. The proprietary roll-to-roll operation enables continuous depositions of sophisticated multi-layer structures. The deposition methods include sputtering and plasma-enhanced chemical vapor depositions. Spectrumsplitting triple-junction solar cell design, manufacturing processes, and product applications are presented.

Large Area Position Sensitive Detector Based on Amorphous Silicon Technology

1993 ◽  
Vol 297 ◽  
Author(s):  
E. Fortunato ◽  
M. Vieira ◽  
L. Ferreira ◽  
C.N. Carvalho ◽  
G. Lavareda ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Chemical Vapor ◽  
Position Sensitive Detector ◽  
Back Side ◽  
Sensitive Detector ◽  
Metal Contacts ◽  
Key Factors ◽  
Large Area ◽  
Position Sensitive

We have developed a rectangular dual-axis large area Position Sensitive Detector (PSD), with 5 cm × 5 cm detection area, based on PIN hydrogenated amorphous silicon (a-Si:H) technology, produced by Plasma Enhanced Chemical Vapor Deposition (PECVD). The metal contacts are located in the four edges of the detected area, two of them located on the back side of the ITO/PIN/A1 structure and the others two located in the front side. The key factors of the detectors resolution and linearity are the thickness uniformity of the different layers, the geometry and the contacts location. Besides that, edge effects on the sensor's corner disturb the linearity of the detector. In this paper we present results concerning the linearity of the detector as well as its optoelectronic characteristics and the role of the i-layer thickness on the final sensor performances.

Computational Fluid Dynamics Study on the Effect of Inlet Modifications of Gas-Liquid Cylindrical Cyclone (GLCC©) Compact Separators

2017 ◽  
Author(s):  
Srinivas Swaroop Kolla ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Behavior ◽  
Low Cost ◽  
Field Application ◽  
Attractive Alternative ◽  
Inlet Section ◽  
Wide Range ◽  
Cylindrical Cyclone ◽  
Section Design

The Gas-Liquid Cylindrical Cyclone (GLCC©1) is a simple, compact and low-cost separator, which provides an economically attractive alternative to conventional gravity based separators over a wide range of applications. More than 6,500 GLCC©’s have been installed in the field to date around the world over the past 2 decades. The GLCC© inlet section design is a key parameter, which is crucial for its performance and proper operation. The flow behavior in the GLCC© body is highly dependent on the fluid velocities generated at the reduced area nozzle inlet. An earlier study (Kolla et al. [4]) recommended design modifications to the inlet section, based on safety and structural robustness. It is important to ensure that these proposed configuration modifications do not adversely affect the flow behavior at the inlet and the overall performance of the GLCC©. This study is carried out for a specific GLCC© field application, separating light oil, steam flooded wells in Minas, Indonesia. Computational Fluid Dynamics (CFD) software is used to analyze the hydrodynamics of flow with the proposed modifications of the inlet section for GLCC© field applications.

scholarly journals High-Sensitivity Flexible Pressure Sensor-Based 3D CNTs Sponge for Human–Computer Interaction

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3465
Author(s):  
Jianli Cui ◽  
Xueli Nan ◽  
Guirong Shao ◽  
Huixia Sun
Keyword(s):  
Pressure Sensor ◽  
High Performance ◽  
Large Scale ◽  
Low Cost ◽  
Pressure Sensors ◽  
Chemical Vapor ◽  
High Sensitivity ◽  
Wearable Electronics ◽  
Wide Range ◽  
Flexible Pressure Sensors

Researchers are showing an increasing interest in high-performance flexible pressure sensors owing to their potential uses in wearable electronics, bionic skin, and human–machine interactions, etc. However, the vast majority of these flexible pressure sensors require extensive nano-architectural design, which both complicates their manufacturing and is time-consuming. Thus, a low-cost technology which can be applied on a large scale is highly desirable for the manufacture of flexible pressure-sensitive materials that have a high sensitivity over a wide range of pressures. This work is based on the use of a three-dimensional elastic porous carbon nanotubes (CNTs) sponge as the conductive layer to fabricate a novel flexible piezoresistive sensor. The synthesis of a CNTs sponge was achieved by chemical vapor deposition, the basic underlying principle governing the sensing behavior of the CNTs sponge-based pressure sensor and was illustrated by employing in situ scanning electron microscopy. The CNTs sponge-based sensor has a quick response time of ~105 ms, a high sensitivity extending across a broad pressure range (less than 10 kPa for 809 kPa−1) and possesses an outstanding permanence over 4,000 cycles. Furthermore, a 16-pixel wireless sensor system was designed and a series of applications have been demonstrated. Its potential applications in the visualizing pressure distribution and an example of human–machine communication were also demonstrated.

Deposition of High Quality Amorphous Silicon by a New “Hot Wire” CVD Technique

1999 ◽  
Vol 557 ◽  
Author(s):  
Scott Morrison ◽  
Ken Coates ◽  
Jianping Xi ◽  
Arun Madan
Keyword(s):  
Amorphous Silicon ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Hot Wire ◽  
Large Area ◽  
New Approach ◽  
Vapor Deposition Technique ◽  
Photovoltaic Applications ◽  
Technical Issues ◽  
Silicon Materials

AbstractFor the “Hot Wire” chemical vapor deposition technique (HWCVD) method to be applicable for photovoltaic applications, certain critical technical issues need to be addressed and resolved such as: lifetime of the filaments, reproducibility, large area demonstration of the material and stable devices. We have developed a new approach (patent applied for) which addresses some of these problems, specifically longevity of the filaments and reproducibility of the materials produced. The new filament material used has so far shown no appreciable degradation even after deposition of >200 μm of amorphous silicon (a-Si). We report that this can produce “state-ofthe-art” a-Si with a dark conductivity of <10-10 (Ohm*cm)-1 and photoconductivity of >10-5 (Ohm*cm)-1 this material can also be doped p- or n-type. We also provide data using XRD as well as the Raman spectra. These materials have been incorporated into simple Schottky barrier structures. The development of microcrystalline silicon materials is also discussed.

Scale-up of oCVD: large-area conductive polymer thin films for next-generation electronics

2015 ◽  
Vol 2 (2) ◽  
pp. 221-227 ◽  
Author(s):  
Peter Kovacik ◽  
Gabriella del Hierro ◽  
William Livernois ◽  
Karen K. Gleason
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Polymer Films ◽  
Vapor Deposition ◽  
Low Cost ◽  
Scale Up ◽  
Conductive Polymer ◽  
Chemical Vapor ◽  
Next Generation ◽  
Large Area

We demonstrate large-area conductive polymer films using oxidative chemical vapor deposition and apply them to low-cost and durable conductive textiles.

Hydrogenated Amorphous Silicon Alloys Prepared by CVD of Higher Silanes

1986 ◽  
Vol 70 ◽  
Author(s):  
Masud Akhtar ◽  
Herbert A. Weaklie
Keyword(s):  
Amorphous Silicon ◽  
Band Gap ◽  
Plasma Deposition ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Wide Band ◽  
Dark Conductivity ◽  
Attractive Alternative ◽  
Silicon Alloys ◽  
Hydrogenated Amorphous

ABSTRACTHydrogenated amorphous silicon may be deposited at relatively low temperatures, where the density of defects may be expected to be low, by the chemical vapor deposition (CVD) of higher silanes. This method is an attractive alternative to plasma deposition techniques. We describe here the preparation of a-Si:H and related alloys incorporating carbon, germanium, and fluorine. a-Si:H films were deposited on heated substrates in the range 365°C-445°C by CVD of Si2H6 and Si3H8. The optical gap (Eg) ranged from 1.4 to 1.7 eV and the properties of films deposited from either Si2 H6 or Si3 H8 were quite similar. Wide band gap (Eg=2 eV) alloys of a-SiC:H doped with boron were prepared by CVD of disilane, methyl silane, and diborane. We also prepared variable band gap a-SiC:H alloys by substituting F2C= CFH for methylsilane, and these films were found to have approximately 1–2% fluorine incorporated. The dark conductivity of the boron doped a-SiC:H alloys dep~sited from either carbon source ranged from ix10-7 to 6x10-7 (ohm-cm)-1. We also prepared low band aap alloys of Si and Ge by CVD of trisilane and germane. The band gap of a film containing 20% Ge was 1.5 eV; however, the photoconductivity of the film was relatively low.

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