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British English vs. American English: Vocabulary

British English vs. American English: Vocabulary

Nano silicon solar cells: my Group at LinkedIn click here

Nano silicon solar cells: my Group at LinkedIn click here: my Group at LinkedIn click here

my Group at LinkedIn click here

Nano silicon solar cells: How do solar panels work ? To answer this questi...

Nano silicon solar cells: How do solar panels work ?
 To answer this questi...: How do solar panels work ?    To answer this question all you have to do is watch this video..... Enjoy watching ....

Methods

Si-NW growth

Silicon nano-wires were synthesized in a two-step growth process via V LS mechanism. At first, the gallium layer of various thicknesses was deposited onto soda-lime glass and Si/SiO₂ substrates via thermal evaporation. SiO₂ layer of 1 nm thickness was used as a barrier to prevent possible diffusion of Ga into Si. The thickness of the Ga layer was varied between 7.5 and 100 nm.

The samples were then loaded into an RF-PECVD reactor with radio frequency of 13.56 MHz and left for 4 h. Hydrogen gas was introduced into the chamber, while the substrate, coated with Ga layer, is being heated up to the growth temperature. Prior to introduction of the precursor gas, hydrogen plasma was created for 5 min in order to remove possible contamination and gallium oxide layer from the substrate. Si-lane (SiH₄) was used as Si source. Gas flow rates, RF power, chamber pressure and deposition duration were process variables that have been investigated in detail and will be reported elsewhere.

Fabrication of bistable memory device

For the fabrication of a bistable memory device, glass substrate was used. Al contacts were deposited by thermal evaporation. Two silicon nitride (Si₃N₄) dielectric layers of 20 nm each were deposited in a PECVD system, sandwiching Si-NWs between the bottom and top electrodes. Si-NWs were grown for 30 min from 100-nm Ga catalyst layer at 400°C. After the Si₃N₄/Si-NW/Si₃N₄/Al/glass structure was fabricated, the second layer of Al contacts was evaporated to finalize the device. The device characteristics were tested by I-V and data retention time measurements.

Fabrication of Schlocky diode

Sin W-based Schlocky diodes were fabricated by growing the Si-NWs directly on glass substrate from 50 nm Ga at 400°C for 20 min with subsequent evaporation of both Al contacts on top of the nano-wires. The device characteristics were tested via I-V measurements.

Fabrication of solar cells

During solar cell fabrication, a glass substrate covered with transparent conductive oxide (TCO) layer (the details of the layer will be reported elsewhere) was utilized. Si-NWs were grown on top of this layer from 50 nm Ga at 400°C for 40 min. Nano-wires for the solar cell were grown using additional phosphine in the reaction chamber for n-type doping of the nano-wires. After the nano-wire growth Al dots were evaporated for top contact.

Background

Silicon nano-wires (Si-NWs) have attracted the attention of many researchers due to their structural, optical, electrical and thermoelectric properties. They are expected to be important building blocks in the future nano-electronic and phonic devices including solar cells, field-effect transistors, memory devices and chemical and biomedical sensors. Owing to their compatibility with the Si-base technology, Si-NWs can be used not only as the functional units of the devices but also as the interconnects .

Various methods have been reported for Si-NW fabrication, including both bottom-up and top-down techniques. Bottom-up growth methods include laser ablation, evaporation, solution-based methods and chemical vapor deposition (CVD). The CVD growth usually takes place via vapor-liquid-solid (VLS) route . Many catalyst materials, mainly metals including Au, Al, Ni, Fe and Ag, have been used for the Si-NW growth . Among these metals, Au as catalyst has been the most popular and most widely investigated due to its chemical inertness and low eutectic temperature of Au-Si system. However, Au introduces deep impurity levels in Si band-gap and degrades the charge carrier mobility . Therefore, alternative catalyst investigation is of crucial importance.

One of the important parameters when considering the nano-wire fabrication process is the growth temperature, as this can determine the variety of substrates that could be used, especially when there is a prefabricated layer of some temperature-dependent material. The nano-wire growth temperature is determined by the eutectic temperature of the catalyst-precursor alloy ; thus, the low-temperature growth will depend on the appropriate catalysts choice. Considering the characteristics of Ga, including the Ga/Si alloy low eutectic point of 29.774°C, wide temperature range for silicon solubility and its non-reactivity to form solid compound with silicon, Ga has been suggested as a good alternative to Au to grow Si-NWs at low-temperatures. It is important to note that Ga does not act as catalyst for the decomposition of precursor gas as it does not assist the dissociation of SiH₄ below its thermal decomposition point. Therefore, Ga acts only as a solvent, and the decomposition is achieved by plasma treatment (by the use of plasma-enhanced chemical vapor deposition (PECVD) system) .

In this study, Ga catalyst is used with an aim to grow Si-NWs at a lowest temperature using PECVD technique. The growth temperature was varied between 100°C and 400°C. The grown nano-structures were characterized using scanning electron microscopy (SEM), Ultra Violet Visible spectroscopy (UV-Vis) and Ra man spectroscopy.

Electronic memory devices play a vital role in our everyday life. In the last a few decades, major progress has been observed focusing on the miniaturization of the memory size cell while increasing its density. However, materials and fabrication techniques are reaching their limits. Alternative materials and architecture of memories, as well as manufacturing processes, are considered. In order to achieve this, different types of memories such as polymer, phase change and resistance have been reported in the literature . Two-terminal non-volatile is one of the most promising memory types for fulfilling the aim of combining low cost, high density and small size devices . Therefore in this study, we present a two-terminal non-volatile memory based on Si-NWs. The suitability and potential use of Si-NWs for storage medium are investigated. The electrical behavior of these devices was examined mainly in terms of current–voltage (IV) characteristics and data retention time (current-time) measurements.

Schlocky diodes made of bulk materials do not dissipate heat quickly; hence, performance and lifespan of the device are reduced. Recently, one-dimensional (1D) nano-structures and their incorporation into Schlocky diodes have been studied extensively. Due to their high surface-to-volume ratio and space between the nano-wires, diodes made of 1D nano-structure arrays can dissipate heat faster due to individual input from each wire. Therefore, integration of these nano-materials into the device will enhance its performance and lifespan . The as-grown Si-NWs fabricated in this study were also used in a Schlocky diode, and the electrical behavior of the device is analyzed.

Solar cells fabricated with nano-wires have shown several advantages when compared to wafer-based solar cells; some of them include trapping of light, less reflection and enhanced band-gap tuning. Although these advantages do not compete to attain efficiency more than efficiencies reported until today, they help in obtaining same efficiency or less by reducing the quantity and quality of the material. Nano-wires deposited by our growth method can have a number of benefits due to their possible fabrication directly on cheaper substrates including steel, bricks, aluminum foil and conductive glass, thus reducing the price of the solar cells based on these structures. In this study, Si NW-based Schlocky solar cells were fabricated and their performance tested.

Abstract

This paper represents the lowest growth temperature for silicon nano-wires (SiNWs) via a vapor-liquid–solid method, which has ever been reported in the literature. The nano-wires were grown using plasma-enhanced chemical vapor deposition technique at temperatures as low as 150°C using gallium as the catalyst. This study investigates the structure and the size of the grown silicon nano-structure as functions of growth temperature and catalyst layer thickness. Moreover, the choice of the growth temperature determines the thickness of the catalyst layer to be used.

The electrical and optical characteristics of the nano-wires were tested by incorporating them in photovoltaic solar cells, two terminal bistable memory devices and Schottky diode. With further optimisation of the growth parameters, SiNWs, grown by our method, have promising future for incorporation into high performance electronic and optical devices.

Keywords:

Silicon nano-wire; Nano-tree; Gallium; PECVD; Solar cell; Schottky diode; Bistable memory

http://www.4electron.com/phpbb/viewtopic.php?f=69&t=3286

http://uqu.edu.sa/page/ar/12486

http://www.youtube.com/watch?v=Zu6oly462_w

http://www.dbaasco.com/vb/showthread.php?t=1397 # ixzz2MEKIc2Uc

http://ar.wikipedia.org/wiki/%D8%AE%D9%84%D8%A7%D9%8A%D8%A7_%D8%A7%D9%84%D8%B3%D9%8A%D9%84%D9%8A%D9%83%D9%88%D9%86_%D8%A7%D9%84%D8%B4%D9%85%D8%B3%D9%8A%D8%A9_%D8%A8%D8%AA%D9%82%D9%86%D9%8A%D8%A9_%D8%A7%D9%84%D9%86%D8%A7%D9%86%D9%88#.D9.85.D8.B1.D8.A7.D8.AC.D8.B9

http://gehadzizo26.wix.com/nanossc

http://www.nanoscalereslett.com/content/8/1/83

    <div style="margin:10px 10px 10px 10px; padding-left:10px;text-align:left; border-left:10px solid #acacac;">
        <span style="font-size:14px; padding-bottom:5px; font-weight:bold;">Exploration of nano-element array architectures for substrate solar cells using an a-Si:H absorber</span><br/>
        <span>J. Appl. Phys. <strong>111</strong>, 123103 (2012)<br/>
        <a href="http://link.aip.org/link/doi/10.1063/1.4729539">http://dx.doi.org/10.1063/1.4729539</a></span>
    </div>

This video explains in a simplified manner how the cell works.

Has produced the first solar cell in 1986 and was its efficiency 1% they turned only 1% of the light energy falling upon to electrical energy and after the scientists used organic compounds new in the nineties of the last century increased efficiency to about 5%, and scientists hope to raise the efficiency to 10 % in a few years and makes those modern technology attractive for business investment. 

While dependent conventional solar cells on inorganic, such as alloy copper or gallium "metal with a white slash blue" and silicon which materials may not be always available either organic solar cells, they consist mainly of carbon molecules, hydrogen and oxygen are available in nature.

The researchers suggest that organic solar cells can be operated toys or screens small flexible can a matter in or you recharge your batteries portable devices such as telephone, etc. Without a doubt, convert the sun's energy into electricity by materials do not cause any pollution to the environment is great and the researchers hope that solar energy become soon a major source of energy to replace fossil fuel "oil and natural gas" as well as once installed solar cells, the user will get the power after it has always been free.

And increase electronics enhanced complexity of silicon cells used in buildings and various devices as an additional component you specific tasks but what would happen if the solar cells made ​​of material other than silicon?Ask me He was told that the new solar cell reached by the scientists made ​​from organic materials and the advantage of being flexible, lightweight and much cheaper than conventional solar cells is "organic" because it consists mainly of carbon, however, the main obstacle to organic solar cells to their efficiency in converting light into electricity very much lower compared to silicon cells.

 
Electronic traps .. And other obstacles
Consisting solar cell conventional thin layer semiconductor"crystalline solid resistance medium between conductors metallic and insulating materials" squeezed between two electricians and when it falls light on the semiconductor raised electrons near enough to "take off" the same restrictions installed by leaving behind holes and works an electric field is equipped with bipolar Ali urged electrons which carry a negative charge and the gaps" that carry a positive charge "to move the parties interviewers from the solar cell and the process is relatively easy in the semiconductor inorganic, such as silicon, but in the case of organic materials, we find that the force electron linking the largest gap by about a hundred times. Furthermore, the organic material is often a "trap" such as highway barricades impede the movement of electrons.
In spite of the modest efficiency of organic solar cells but other characteristics such as flexibility, light weight, durability and low cost make it attractive to a large extent this in addition to the possibility of integration in other materials due to the flexible nature .. Starting from fabrics to plastics "plastics" to the materials used in building roofs.

Nearing solar energy to become a reliable source of energy engineers devised electricians U.S. method for the manufacture of solar cells if placed side by side with other modern devices. To become a very economical source of energy for the future.

And push scientists to manufacture a new type of solar cells that are not in the same efficient traditional sources, but the cheaper ones and much more useful and widely used and known that solar cells or photo-voltaic cells turning light into electricity and can run a lot of devices from computers "computers" to satellites and solar cell "photo-voltaic" is an electronic cell generated electric driving force their exposure to optical radiation.

Every minute launches sun on the planet a tremendous amount of energy, enough to consume all the inhabitants of the land in an entire year! Unfortunately, the conversion of all those solar horrific to electricity is very expensive and most solar cells are made of silicon silicon element metal and found in abundance in the earth's crust on the body dioxide silicon sand and this needs like microchips to manufacturing processes difficult include the use of room clean and booths circle of air and as a result, the cost of generating electricity from solar energy is about four times as much as the cost generated by conventional means and the good news here is that developments are taking place at a time afoot in the field of plastics plastics and nanotechnology nanotechnology for making cells cheap and flexible can "sprinkled "on the walls or even printed on paper or fabrics!
One of the flaws in the solar cells, "photo-voltaic" traditional silicon-based is that it is solid.

How do solar panels work ? 

 To answer this question all you have to do is watch this video.....

Enjoy watching ....

Some problems with the use of solar energy:

• The most important problem facing researchers in the fields of solar energy utilization is the presence of dust and try to clean solar devices it has demonstrated ongoing research on this topic that more than 50% of the effectiveness of solar energy lost in the case of non-cleaning device future to the sun for a month.

The best way to get rid of the dust is the use of continuous cleaning methods at intervals not exceeding three days for each period and these methods vary from country to country based on the nature of the dust and the nature of the weather in that country.

• The second problem is storage of solar energy and take advantage of them during the night or on cloudy days or dusty days and depends storage of solar energy on the nature and amount of solar energy, and the type of use and the period of use in addition to the total cost of the way storage and prefers not to use devices for storage to reduce the cost and benefit rather than that of solar energy directly only when its existence and is the subject of solar energy storage of topics that need to be more scientific research and new discoveries.

The storage temperature by water and rocks the best ways in the present time. As for the storage of electrical energy is still common method is to use liquid batteries (lead-acid batteries).

Types of solar cells:

Been manufacturing solar cells of different materials but most of these materials are rare nature first properties toxic polluting or complex manufacturing and expensive and some are still under study and research and it has focused attention on the solar cell manufacturing silicon so as to provide an element silicon in nature as well as to scientists The researchers were able to study this element extensive study and identified the various properties and suitability for the manufacture of solar crystal cells  cracked and crystallization.

1- solar silicon crystal cells:

These cells are made ​​of silicon through the development of silicon rods single or multiple crystallization then Aarb to chips and treated chemically and physically through various stages to reach solar cells.High efficiency of these cells ranging between 9 - 17% and mono silicon cells crystallization expensive in terms of technical difficulty and energy consumption, while many silicon crystallization cells are less expensive than single-crystallization and also less efficient.

2 - cells solar silicon Almoravid (cracked crystallization):

Material of these cells with a silicon where configuration crystal cracked the presence of the element hydrogen or other elements introduced intentionally to earn properties electrical characteristic and cells silicon Amorphous affordable for cells crystalline silicon where deposition layer stripe thin using small quantities of raw materials used in the few operations compared manufacturing processes crystalline . The manufacturing Amorphous silicon cells more and suitable for continuous self-Architectures.
Ranging efficiency cells of this article is between 4 - 9% for the large surface area and a little more than for a small surface area and that was influenced by the stability of the solar radiation.

But there is an important question must ask yourself namely
how solar cells work?

To answer this question all you have to do is watch this video

then you will be able to understand how solar cells work 

and thanks for watching

In this website we will taking about Nano Silicon Solar Cells 

At first you must know what is the solar cells and what is nanotechnology and how they are working with each other in addition to silicon to born Nano Silicon Solar Cells.

What is a Solar Cells?

A solar cell or photo-voltaic cell is a device which generates electricity directly from visible light by means of the photo-voltaic effect. In order to generate useful power, it is necessary to connect a number of cells together to form a solar panel, also known as a photo-voltaic module. There is more about the the different types of solar cell here. The nominal output voltage of a solar panel is usually 12 Volts, and they may be used singly or wired together into an array. The number and size required is determined by the available light and the amount of energy required.

What is Nanotechnology?

A basic definition: Nanotechnology is the engineering of functional systems at the molecular scale. This covers both current work and concepts that are more advanced.In its original sense, 'nanotechnology' refers to the projected ability to construct items from the bottom up, using techniques and tools being developed today to make complete, high performance products.