Introduction
To begin this report, we will describe what exactly are “Compound Semiconductor Solar Cells”, by first separating the two main parts of “Compound Semiconductor” and “Solar Cell”. Firstly, a compound semiconductor is a semiconductor made up of two or more elements, such as Gallium Arsenide (GaAs), which is composed of Gallium (Ga) from Group III and Arsenic (As) from Group V. Compound Semiconductors have several important advantages over the conventional semiconductors which are made from Silicon (Si) and Germanium (Ge), such as a higher electron carrier mobility, thus the use of n-channel field effect transistors made from GaAs are capable of being faster than it’s Si counterpart. Another benefit of the use of compound semiconductors are that they are able to withstand higher temperatures and radiation damage, allowing for a wider range of uses as compared to the conventional semiconductors. However, with these advantages, there are some disadvantages as well, as the materials needed for making compound semiconductors evaporate at different rates, thus needing a low pressure environment for fabrication. This disadvantage leads to a higher cost and
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The crucible containing the Gallium and Arsenic is vacuum pumped and purged with inert gas, then heated to a very high temperature of between 400 to 600 degrees Celsius, melting the boron oxide cylinder to prevent evaporation. At about 817 degrees Celsius, the arsenic melts and combines with gallium in an exothermic reaction, continued heating to above the melting point of synthesized GaAs, 1238 degrees Celsius, homogenizes the GaAs. At the end of the synthesis, the crucible is turned upside down to remove the GaAs ingot and to separate the boron oxide, after etching the material, the next step in manufacturing can be done, single crystal
...in with an advance nanowire production. The modified version help improve the bacteria’s ability to isolate uranium proportionally. With the increased ability of isolating the uranium the bacteria was able to clear the uranium out much faster. With the increased nanowires it was also protected even more so. Reguera has patents allowing her to build on her research. Possibly leading to developments in microbial fuel cells.
Ultra high temperature ceramics (UHTCs) are materials rarely found in nature, characterized by high melting points, hardness, thermal conductivities (if compared to other ceramics), good wear resistance and mechanical strength.1,2,3 Besides, they are chemically and thermally stable under a variety of conditions due to their high negative free energy of formation.1,3
Arsenic is element 33 on the periodic table and is in Group 15. Arsenic is obviously an extremely poisonous element; however, some people have found arsenic to have a restorative effect on them. Chemically, arsenic is a metalloid. Two common forms of arsenic are gray and yellow. (see Figure 1-A) Element 33 has an atomic weight of 74.9216 and the chemical symbol of As. It boils at 613ºC, melts at 817ºC, and has a density of 5.72. (see Figure 2-A) The element has been known for centuries and can be easily obtained from ores such as arsenopyrite (FeAsS), realgar (As2S2), orpiment (As2S3), and arsenic trioxide (As2O3). There are many uses for arsenic. Among them is in the manufacturing of glass to eliminate the air bubbles and the green color caused by contaminated iron compounds. Arsenic is also added to materials such as lead and copper alloys to increase the strength and better the corrosion resistance. Although it is well known that arsenic is often used in tales (both true and otherwise) as a killing agent, arsenic has been used as a curative as well. Before penicillin was introduced, arsenic played a significant role in the treatment of syphilis. Other good uses for element 33 are as insecticides and semiconductors. Gallium arsenide (GaAs) is a known semiconductor that is also used as a laser material. A good test for the detection of arsenic is the Marsh test, invented by James Marsh, an English chemist.
The symbol “As” from the periodic table, belongs to the chemical element Arsenic. Its located in group 15, period 4, and is clasificat as semi-metals. Arsenic’s atomic number is 33, and has a density of 5.776 grams per cubic centimeter. Arsenic melting point is 1090 K (817°C or 1503°F) and the boiling point is 887 K (614°C or 1137°F). The element specific gravities are 1.97 and 5.73, they are respectively to his two solid modifications: yellow, and grey (or metallic). Arsenic’s appearance is steel grey, very brittle, crystalline, and is classified as a semi-metal since it has properties of both.
Transducers contain the crystal lead zirconate titanate, designed and fitted into the probe in thin, rectangular slabs referred to as elements. A conducting layer of silver covers the front and back faces of each element forming electrodes and having electrical leads attached where the alternating voltage is applied.(Fairhead and Whittingham, 2012)
Gallium is a metal that was discovered in 1875 by Paul Emile Lecoq De Boisbaudren and is a “byproduct of the manufacture of aluminum” (“Gallium.” Web). Gallium has a low melting point of 29.76°c which is just slightly above room temperature. But even with an unusually low melting temperature, gallium has a very high boiling point of 2204°c. “Gallium expands by 3.1% when it solidifies” (“Gallium.” Avalon). Gallium was an element that was predicted by Dmitri Mendeleev and it “Validated his periodic table of elements” (“Gallium.” Avalon). When in solid form, Gallium has a Silver and reflective appearance.
At i) the photoelectron can recombine directly with its hole pair of positive where the arrow shows the electron (negative) goes directly to the hole pairs. Next, the second part ii) represent the photoelectron can recombine at a trap as it stop at the middle of the band gap and for final part, iii) states that a photoelectron can transfer to an absorbed species either to encourage a particular (redox) reaction or which is considered a contaminant (Gao et al., 2009).
One of HP's innovative efforts include innovations in their use of resources. One of these innovations is the development of the transparent transistor technology which utilizes low-cost and high-efficiency materials such as tin and zinc. With minimal environmental impact, these materials also allow HP for faster mobility of resources world-wide,...
Before I go in to detail about usage and implementation of solar cells, let me explain just how they work. Solar cells, also known as photovoltaic cells (Photo= light Voltaic=electricity) capture photons, convert them into electrons, and use these electrons to transfer energy to whatever you want to power. To do this, solar cells are made with a material called a semiconductor, which, for solar cells is almost always silicon. When light hits this material, it causes electrons to break loose and flow throughout the material. By placing metal plates on the solar cell, we can capture this flow of electrons, otherwise known as current. Using the equation Power= Volts * Current, you can calculate the voltage output of a cell, which, using silicon, is about 1.1 volts- a 25% or so efficiency.
Yuji, A. (2001). X-Ray Absorption spectroscopic investigation of arsenite and arsenate adsorption at the aluiminum oxide water interface. Journal of Colloid and Interface Science ,
Gallium is a chemical element with the symbol Ga. Gallium is a soft silvery blue at standard temperature and pressure, it's a brittle solid at low temperature. Gallium is a non-toxic chemical for humans, gallium is used to make a thermometer. most of us use gallium for an everyday thing, they are used to make mobile phones, optoelectronics, solar panels, and LEDs. It is used for mining a mining tool, the thing they mind for with gallium is aluminum and zinc.
Solar energy products can range from solar panels to cell phone charges, and everything in between. Solar energy is becoming a popular way to fuel homes throughout the United States. All over the country, people are covering their rooftops with solar panels, heating their pools with solar energy, and even turn on the lights in their homes with solar energy. Solar power is quickly becoming America’s most popular form o...
Although Solar Energy is a flexible source of where energy could be directly or indirectly converted into forms of energy, it’s still not perfect. With its inefficiency, scientists are trying to find alternative solution to store solar cells for as long as possible. The main process of capturing solar energy happens at the nanoscale. With solar cells, it gets more efficient the tinier it gets. The converting rate of solar energy is equally price competitive as fossil fuel, with a dollar per watt of solar energy. With the help of nanotechnology, it could help raise solar energy conversion efficiency and help lower costs making it the ultimate method of raw energy conversion. To make sure the process of generating energy is kept at a low cost and energy output...
Steel: (for all intents and purposes) was invented in 1855 by Henry Bessemer(Mary Bellis). Science the amazing innovation that has changed the world incredible things have been made from the material from bridged cables and cross beams to arresting wires on aircraft carriers that stop monumental force and speed. It is truly an amazing martial, but eventually it snaps, breaks or tears due to the separation of the molecules. Also steel is not the most flexible material there is which may sound good for what it is used for, construction. You wouldn’t want the floor to shift from under but, what about in areas that have a consent threat of earthquakes having a material that is rigid when needed and flexible when needed would be an invaluable asset to construction companies in many countries. Also at $600-$900 per ton(Platts Mcgraw hill financial) it isn’t the most inexpensive material that could be chosen. Chemically is there a better material that could be used in the place of steel that is stronger more flexible and can be produced for a cheaper price than the normal steel that we use today? First, the choice of spider silk seems like a great choice. Mother nature seems to be the greatest designer of all made of different sections of proteins of extremely ridged and at the same time extremely elastic strings of proteins, that when braided together are 5 times stronger than steel and relatively free to produce as long as the spiders are kept healthy. What makes the proteins so strong? They are linked together almost like thousands of Lego’s linked together which by its self does not sound very strong, but just take 3 and pull length wise and try to pull them apart, it's almost impossible. The same concept is used in the spider's silk...
The photovoltaic effect, electricity can be created directly from sunlight. Some semi-conductor materials that are exposed to sunlight can create electron-hole pairs, which can be collected to produce electricity. This occurs when photons have energy above a certain threshold. These photons have shorter wavelengths. In silicon, the threshold for electron-hole production is in the infrared region of the electromagnetic spectrum.