emad المدير
المحافظه أو الولايه : suez عدد المساهمات : 765 نقاط : 1926 السٌّمعَة : 45 تاريخ التسجيل : 19/11/2009 العمر \ Old : 32 العمل/الترفيه : مهندس كمبيوتر المزاج : مرح
بطاقة الشخصية emad:
| موضوع: semiconductors 9/5/2010, 6:33 pm | |
| بسم الله الرحمن الرحيمA semiconductor is a material that has an electrical conductivity between that of a conductor and an insulator, that is, generally in the range 103 siemens per centimeter to 10−8 S/cm. Devices made from semiconductor materials are the foundation of modern electronics, including radio, computers, telephones, and many other devices. Semiconductor devices include the various types of transistor, solar cells, many kinds of diodes including the light-emitting diode, the silicon controlled rectifier, and digital and analog integrated circuits. Solar photovoltaic panels are large semiconductor devices that directly convert light energy into electrical energy. An external electrical field may change a semiconductor's resistivity. In a metallic conductor, current is carried by the flow of electrons. In semiconductors, current can be carried either by the flow of electrons or by the flow of positively-charged "holes" in the electron structure of the material. Common semiconducting materials are crystalline solids but amorphous and liquid semiconductors are known, such as mixtures of arsenic, selenium and tellurium in a variety of proportions. They share with better known semiconductors intermediate conductivity and a rapid variation of conductivity with temperature but lack the rigid crystalline structure of conventional semiconductors such as silicon and so are relatively insensitive to impurities and radiation damage. Silicon is used to create most semiconductors commercially. Dozens of other materials are used, including germanium, gallium arsenide, and silicon carbide. A pure semiconductor is often called an “intrinsic” semiconductor. The conductivity, or ability to conduct, of common semiconductor materials can be drastically changed by adding other elements, called “impurities” to the melted intrinsic material and then allowing the melt to solidify into a new and different crystal. This process is called "doping".[1] ............... Semiconductors Shockley, Bardeen and Brattain, the men behind the transistor, were awarded the 1956 Nobel Prize in Physics. With the invention of the transistor, the extraordinary usefulness of semiconductors was recognized. شكر خاص من thegood2010 .. | |
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dark_punisher47 مدير الاعضاء
المحافظه أو الولايه : خليل الرحمن (الخليل) عدد المساهمات : 489 نقاط : 541 السٌّمعَة : 15 تاريخ التسجيل : 28/10/2012 العمر \ Old : 29
بطاقة الشخصية emad:
| موضوع: رد: semiconductors 24/1/2013, 7:27 pm | |
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amr مدير الاعضاء
المحافظه أو الولايه : السويس عدد المساهمات : 352 نقاط : 427 السٌّمعَة : 17 تاريخ التسجيل : 01/12/2009 العمر \ Old : 28 العمل/الترفيه : طالب المزاج : جيد جدااا
بطاقة الشخصية emad:
| موضوع: رد: semiconductors 29/4/2013, 11:55 am | |
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