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Semiconductors materials


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Semiconductors materials

  1. 1. Semiconductor MaterialsSubmitted by: Arabi RadwanSubmitted by: karim ahmed abu amo
  2. 2. Semiconductors• Introduction• Definition & Function• Formation or production• Crystal structure• Application
  3. 3. IntroductionConductor: allow current to flowbecause they are made ofmaterials with abundant offree electron.Insulator: restrict current to flowbecause they have smallnumbers of free electron.Semiconductor :have enoughelectrons to allow somecurrent to flow but not enoghto allow so easily.
  4. 4. Electrical conduction is the result ofelectron motion within each bandFor a conductor, conduction bands and valence bands are notseparated and there is therefore no energy gap. The conductionband is then partially occupied (even at low temperatures),resulting in a “high” electrical conductivity.
  5. 5. What is a Semiconductor A semiconductor is a material that hasintermediate conductivity between aconductor and an insulator Also called "III-V" materials sincesemiconductor elements are ingroups III and V of the periodic tableof chemical elements.Examples are silicon (14Si),germanium(32Ge)
  6. 6. Doping• Doping : is the addition ofminute quantities of non-silicon material tosemiconductor.• This added materialchanges the number ofvailable free electron .• Doping process producestwo groups ofsemiconductors: thenegative charge conductor(n-type) and the positivecharge conductor (p-type)
  7. 7. N-type and P-type• As (phosphorus), a Group Velement, introduces conductionelectrons and creates N-typesilicon (called a Donor).• B (Boron), a Group III element,introduces holes and creates P-type silicon, and is called anacceptor.
  8. 8. Production-
  9. 9. Examples Diode: A one wayvalve Allow current toflow in only onedirection Transistor: ElectronicSwitch
  10. 10. Types of Diodes Power diode (500-1000Volt) Used in power circuits Zener Diode Allow current to flow inreverse biased(only at specificvolt) Light emitting diode(LED) Used in automobile Required (1.5 -2 volt 30 mA)
  11. 11. Diode Schematic symbol How it worksAnode Cathode
  12. 12. Reversing polarityof the power source
  13. 13. Applications• Power diode• (AC to DC converter)half wave rectifier
  14. 14. Full wave rectifier(power supply)
  15. 15. Function Semiconductors act as an electrical conductoror insulator depending on chemical alteration It also control and amplify current or voltusing a small voltage or current. Examples: Diode: allow or restrict current to flow Transistors: Amplifying
  16. 16. Automotive alternator• Battery charging• Six diodes(rectifier Bridge)
  17. 17. Transistors
  18. 18. Analogy• Use a low current tocontrol a higher current• Act as a switch or gatefor electronic circuit.• Used as an amplifier
  19. 19. Amplification
  20. 20. Applications
  21. 21. Diode Schematic symbol How it worksAnode Cathode
  22. 22. FunctionsSemiconductor devices control and amplifybecause a small voltage or current, allows thesemiconductor to pass or block electricalcurrent.Devices can be fabricated with othercapabilities such as passing electric current inonly one direction, emitting light, mixing andtransforming signals, etc.