16-Chaudhury-Light Emitting Diodes

16-Chaudhury-Light Emitting Diodes - Light Emitting Diodes...

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Light Emitting Diodes Samiran Roy Chaudhury
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Itinerary LEDs Light in a LED Specifics of LEDs Homojunctions and Heterojunctions Surface or Wave/Edge Emitting Textured surface LEDs Organic LEDs Lifetimes of LEDs Future of LEDs
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LEDs Created in 1904 – SiC No need for optical cavities or mirror facets to produce feedback of photons Light created by spontaneous emission as compared to stimulated emission as in laser diodes Qualities: Low cost Low power usage Low power output Simple drive circuitry Does not suffer degradation as badly as lasers Linear output current characteristic Less sensitive to temperature than a laser
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LED Material Characteristics
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Homo or Hetero Homojunction Simple PN structures Lot of problems: Minority carriers recombine with majority carriers away from junction reducing efficiency Surface far from the junction can cause reabsorbtion of photons Can be created by many growth processes: MOCVD, Epitaxy,… Heterojunction Complex PN structures around the junction A fix to the problems with Homojunction Usually realized by epitaxial growth
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Homojunction Vs Heterojunction
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Surface Emitting Diode
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This note was uploaded on 08/23/2011 for the course ECE 3080 taught by Professor Staff during the Spring '08 term at Georgia Tech.

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16-Chaudhury-Light Emitting Diodes - Light Emitting Diodes...

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