The transit was a very rare astronomical event that would not be
seen again for another 105 years.
Observers in north and central
America, and the northern-most parts of South America saw the transit begin
just before local sunset.
The far northwest of America, the
Arctic, the western Pacific, and east Asia witnessed the entire passage.
The UK and Europe, the Middle East,
and eastern African waited for local sunrise to see the closing stages of the
transit.
Venus appeared as a small black dot
moving slowly but surely across the solar disc.
Special events provided safe ways
for the public to see the transit
Some of the best pictures of the
event have been provided by the US space agency's (Nasa) Solar Dynamics
Observatory, which studies the Sun from a position 36,000km above the Earth.
"We get to see Venus in
exquisite detail because of SDO's spatial resolution," said astrophysicist
Dr Lika Guhathakurta.
"SDO is a very special
observatory. It takes images that are about 10 times better than a
high-definition TV and those images are acquired at a temporal cadence of every
10 seconds. This is something we've never had before."
Many citizens keen to get a view of
the transit themselves have been attending special events at universities and
observatories where equipment for safe viewing has been set up. For others, internet streams have provided an easy way to
follow Venus's slow trek.
Scientists
have been observing the transit to test ideas that will help them
probe Earth-like planets elsewhere in the galaxy, and to learn more about Venus
itself and its complex atmosphere.
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I think the fault never happened only from one side other side is also responsible for it in same way. So don't worry take a break and then think deeply both of you that, “is it possible to stay far away from each other or not ???”
Love is not always bring happiness or joyful moment for everybody's life it’s also give huge pain and that person will successfully overcome the sorrows and handle the bad situation and try to continue his love he/she will be the gainer in this world. Always think that love and life both gives us some times pleasure, joyful moment as well as sorrows, if we can live this life with new challenge then why we go backward from the loving one. Love is a priceless gift of GOD which will not easy to earn.
If you have money you can buy a house but not home. If you have money you can buy a Clock but not Time. If you have money you can buy a Bed but not Sleep. If you have money you can buy a Book but not Knowledge. If you have money you can See a Doctor but not Health. If you have money you can buy a Position but not a Respect. If you have money you can buy Blood but not a Life. If you have money you can buy SEX but not LOVE.
So A True love always needs sacrifice. Someone has to be sorry on each time whether if you didn’t do the wrong thing but still say sorry to your lover. Don’t think that if you say sorry to your partner your loving relationship will going to be end, NO never, if you say sorry to your lover then he/she will be proud of you and always hold you higher than anyone else in this world.
A True love never comes with a great enjoyment, its always a gift so you two both think again before break up…
As it appears from most of the historical reviews of semiconductor research, semiconductor devices-preceded by the adjectives early and primitive usually, refer to the crystal rectifiers used for wireless applications in the early 1900’s. In this sense, early 1900’s is regarded as the time when the semiconductor devices first came into application. An investigation into the history of semiconductor research unveils even more primitive and earlier semiconductor devices- they are the semiconductor devices of the 19th century. Pearson and Brattain outlined the developments in semiconductor research before 1900 in [1].
Semiconductor research and semiconductor device application is an interest-entirely of the 20th century, in a more rigorous sense, of the second half of the century- but the roots of this discipline extend to the 19th century, too. Semiconductor properties- as fascinating as negative dynamic resistance of junctions were observed. Use of semiconductors for wireless application began in the 1890’s. The history of semiconductors in the 19th century lacks proper investigation and integration. How semiconductor properties came to scientists’ notice and made debut in the field of application in the pre 1900 era presents us with an untold pre-1900 history of semiconductors.
HISTORY
A Short History of Semiconductor Research before 1900:
The beginning of semiconductor research is marked by Faraday’s 1833 report on negative temperature coefficient of resistance of silver sulfide. This is the first observation of any semiconductor property. In his 1833 paper, “Experimental Researches in Electricity” he disclosed this observation [2].
This observation was in distinction from the usual properties of metals and electrolytes in whose case resistance increase with temperature.
The next significant contributor to semiconductor field in chronological order is the French experimental physicist Edmond Becquerel. In 1839, he reported the observation of photo voltage in the silver chloride coated platinum electrodes [3].
In his experiment, a AgCl coated platinum electrode was immersed in an aqueous nitric acid electrolyte solution. Illumination of the electrode generated photo voltage that altered the EMF produced by the cell, in fact, it produced a reductive (cathodic) photocurrent at the AgCl coated electrode; this was the first reported photovoltaic device. Photo voltage was generated at the Ag/AgCl metal semiconductor contact, Ag at the junction was formed by the absorbed silver clusters in the AgCl electronic states [4] .
The next important decade in the semiconductor research is the decade of 1870. During this period selenium was discovered as a semiconductor, rectification at metal semiconductor interface came into scientists’ notice. In 1873, Willoughby Smith arrived at the discovery of photoconductivity of selenium [5]-[7]. How he reached at this observation has an interesting story.
He was initially working with submarine cables. He set into experiments with selenium for its high resistance, which appeared suitable for his submarine telegraphy. Various experimenters measured the resistance of selenium bars, but the resistance as measured by them under different conditions did not agree at all. Then Smith discovered that the resistance actually depended on the intensity of incident light. When the selenium bars were put inside a box with the sliding cover closed, the resistance was the highest. When glasses of various colors were placed in the way of light, the resistance varied according to the amount of light passing through the glass. But when the cover was removed, the conductivity increased. He also found that the effect was not due to temperature variation.
In 1874 came the most significant discovery in semiconductor field of the 19th century- the discovery of rectification at the contact between certain materials, especially naturally occurring sulfide crystals. Braun’s discovery [8] was related to natural crystals and Schuster’s discovery [9] to contacts between tarnished and untarnished copper wire. In Schuster’s experiment the copper oxide layer on the untarnished wire presumably acted as the semiconductor giving the contact a rectification property. Braun’s experiments were more conclusive and systematic, so well approached that this is generally acknowledged as the first systematically approached study of metal semiconductor contacts.
The first observation of photovoltaic effects in a solid system was made in 1876 [10]. The semiconductor substance was again selenium. W. G. Adams, along with his student R. E. Day was investigating the photoelectric properties of selenium at Cambridge. They discovered that illuminating a junction between selenium and platinum had a photovoltaic effect.
In 1883, Charles Edger Fritts, a New York electrician, built a selenium solar cell [11]. It consisted of thin selenium wafers covered with very thin semi-transparent gold wires and a protective sheet of glass. It is to be noted that, this was the first large area metal semiconductor junction device. However, it was very inefficient (η<1%)>
Although the most significant observations of the 19th century came during the period 1870-1885, the semiconductors had not received any device application for any practical purpose yet. It was not until 1890’s that any field recruited these materials for any practical use. Wireless communication is the first field to employ these materials for practical application.
After Hertz’s demonstration of existence of electromagnetic waves in 1888, a number of scientists got involved with experimenting with these newly discovered waves, and wireless telegraphy became practicable. Among them, Bose was the first person to introduce semiconductors for the reception of wireless waves. In course of determining the various optical properties (polarization, refraction) of electromagnetic waves, he discovered that polarizing crystals had selective conductivity [12]. According to [13], this study led him to discover a galena detector, which is the first semiconductor diode detector of wireless waves. He also used point contacts of metals for detection of millimeter waves, which have I-V characteristics similar to modern semiconductor junctions [14]. Marconi’s 1901 transatlantic receiver is considered the first major use of a semiconductor detector device- that semiconductor device actually originated from Bose’s research in the 1890’s [15].
For another time the focus shifts on Braun. In 1898, he began experiments with wireless telegraphy. He used semiconductors for reception of wireless signals, and in 1901 he realized the advantage of using them for this purpose.
Thus ends the history of semiconductor of the 19th century. The Era of semiconductor begins with Faraday’s silver sulfide in 1833, and at the end of the century it enters the next century of glory with Bose’s introductory application of semiconductors for wireless purposes.
PROSPECTS
Prospects of semiconductor device & why we need it
The semiconductor device research institution was established in Bangladesh about three years ago which an interdisciplinary area is relating to the mechanical engineering, electrical engineering/electronics and computer science. This technology has produced many new products and provided powerful ways of improving the efficiency of the products we use in our daily life. Currently, there is no doubt about the importance of the semiconductor device as an area in science and technology. However, it seems that semiconductor device is not clearly understood, though the word is popularly used in the world and several conferences and books for semiconductor device can be found.
Semiconductor device is a science and technology which deals with a system including mechanisms, electronics, computers, sensors, actuators and so on. It seems that almost all the area, for our daily life all technology was built in the basis of the semiconductor fabrication.
We need the semiconductor devices all the single moment of our daily life as when we go out from home we need automobile vehicles and the vehicles have so many different parts of mechanical devices but the basic of that mechanical device was built by the semiconductor; we need power for our daily life live electricity, but the making of electricity was fully depend on the semiconductor devices materials conditions. A single material can be make so many types of different materials within a very short period of time; the first computer was so much bigger and then the semiconductor devises was not that much isolated and fabricated so much easier way because the research was not that much high level that time; but now a days the computer is as much small as we can carry a computer in our bag. Technology sifted from one dimension to another dimension only by the research of semiconductor devices.
COST
Cost for establishing such facilities:
The capital cost to build and equip a semiconductor fabrication facility has increased exponentially over time from approximately $6 million in 1970, to in excess of $2 billion for next generation 300mm Fabrications coming on-line in the 2001- 2002 timeframe, see figure left axis. If the current trend in fabrication facility costs continues, the cost of a Fabrication will exceed $10 billion by 2007, and may reach $18 billion by 2010. The magnitudes of these costs have led several observers to question whether the industry can afford to continue on the current trend line. At IC Knowledge we believe that while increasing Fabrications costs may change industry dynamics, it is the economics of the facilities that really determine whether these trends can continue. [16]
This 10-year time scale is critical to the industry because semiconductor companies are increasingly adopting smaller scale manufacturing process technologies. The largest and most capable semiconductor manufacturers are developing products based on small line-width technologies with the objective of reaching the market ahead of their competitors. New forecasts for semiconductor fabrication facilities by these leading-edge companies show them to be two to three years ahead of the rest of the market, and their lead appears to be growing. Thus, Moore’s law continues to reflect and influence decision making in the semiconductor industry.
The bellow table will Show you the top 10 companies al over the world who are now having the semiconductor fabrication lab
2003
2000
1997
Intel
$27,103
Intel
$30,298
Intel
$21,746
SAMSUNG Electronics
$10,502
Toshiba
$10,866
NEC
$10,222
Renesas Technology
$7,936
NEC
$10,643
Motorola (Freescale)
$8,067
Texas Instruments
$7,410
Samsung
$10,585
Texas Instruments
$7,352
Toshiba
$7,356
Texas Instruments
$9,202
Toshiba
$7,253
STMicroelectronics
$7,180
STMicroelectronics
$7,890
Hitachi
$6,298
Infineon Technologies
$6,864
Motorola (Freescale)
$7678
Samsung
$5,856
NEC Electronics
$6,312
Hitachi
$7,286
Fujitsu
$4,622
Motorola (Freescale)
$4,628
Infineon Technologies
$6,732
Philips Semiconductor
$4,440
Philips Semiconductors
$4,513
Micron Technology
$6,314
STMicroelectronics
$4,019
Source: Company reports, 2003. [17]
CONCLUSION
A developing country like Bangladesh has many prospects in semiconductor device application. Every single person now a day uses mobile phone, computers, radio, etc. This entire device was made only from semiconductor materials. And as in our country we don’t start manufacturing the semiconductor devices in our labs for the business purpose every single day our country was loosing a lot of money for buying that devices from outside of out country. In an addition most of the mobile phone, chipset of mobile, computer etc was imported from outside of the country, so as a result its not possible for our country to get any benefit. So if we can establish the semiconductor labs and research facility so that not only we can get help from that research also our country will be benefited and we can save billions of dollars every year. [18]
REFERENCES
Books Used for this paper:
[1] G.L Pearson and W. H. Brattain, “History of semiconductor research”, Proc. IRE, vol. 43, pp 1794-1806, Dec. 1955
[2] Faraday, M., Experimental Researches in Electricity, Bernand Quaritch, London (1839)., vol. I, pp. 122-124
[3] Becquerel ,A. E., “On Electric Effects under the Influence of Solar Radiation”, Comtes Rendus de l’Academie des Sciences,Vol. 9 (November 21, 1839),pp.31-33.
[4] G. Calzaferri, D. Brühwiler, S. Glaus, D. Schürch, A. Currao, and C. Leiggener, “Quantum-Sized Silver, Silver Chloride and Silver Sulfide Clusters”, Journal of Imaging Science and Technology, Vol. 45, No. 4 , July/August 2001
[5] Smith, W., “The Action of Light on Selenium”, J. of the Soc. Telegraph Engineers, vol. 2, no. 1(1873), pp. 711-714.
[6]Smith, W., "Effect of Light on Selenium during the passage of an Electric Current", Nature, 20 February 1873, p.303.
[7]Smith W., “Curious effect of Light on Selenium", Scientific American,29 March 1873.
[8] F. Braun, “Uber die Stromleitung durch Schwefelmetalic”, Annalen der Physik and Chemie, vol. 153, no. 4, pp 556-563, 1874. For an English version, see S. M. Sze, Ed., Semiconductor Devices: Pioneering Papers. Singapore and Teaneck, NJ: World Scientific, 1991, pp. 377-380.
[10] Adams, W. G., Day, R. E., “The action of Light on Selenium”, Proceeding of the Royal Society of London, Vol. 25(June, 1876), pp. 113-117.
[11] Fritts, C. E., “A New Form of Selenium Cell:, American Journal of Science, Vol. 26, (December, 1883), pp. 465-472.
[12] Bose, J. C., “On the selective conductivity exhibited by certain polarizing substance,” in Collected Physical Papers. New York, Longmans, Green, 1927, pp 77-76. reproduced in Proc. Of Royal Soc., vol. A65, pp. 166-172, 1899 Reproduced in Proc. Of IEEE, vol. 86, No. 1, January, 1998, pp. 244-247
[13] Sengupta, D.L., Sarkar, T. K., Sen, D., “Centennial of the Semiconductor Diode detector”, Proc. Of the IEEE, vol. 86, no.1, 1998, pp. 235-243
[14] Bose, J. C. , “On the Change of Conductivity of Metallic Particles under Cyclic Electromotive Variation”, originally presented to the British Association at Glasgow, September 1901, reproduced in Collected Physical Papers, J. C. Bose, Ed. , New York, N. Y., Longmans, Green and Co., 1927.
[15] Bondyopadhyay, P. K., "Sir J. C. Bose's Diode Detector Received Marconi's First Transatlantic Wireless Signal Of December 1901 (The "Italian Navy Coherer" Scandal Revisited)," Proc. IEEE, Vol. 86, No. 1, January 1988
Term Paper Used for the history part of semiconductor:
