presentation_prep - My name is Kathryn. I did my...

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My name is Kathryn. I did my mini-project on Light Emitting Diodes, or LEDS, for the course ELEN 4301 Introduction to Semiconductor Devices with Prof. Laibowitz. An overview of the LED operation is presented in this slide. Basically, an LED is a pn junction, where you forward bias it such that majority of the electrons on the n-side are injected over to the p-side and similarly, majority of the holes on the p-side are injected over to the n-side. Then, the injected carriers recombine, and energy is released in the form of light but only in direct semiconductor such as Gallium Nitride. On the other hand, the energy released during the recombination process in indirect semiconductor such as silicon carbide is dissipated as heat. The light emitted can be in ultraviolet, visible, or infrared regions of the spectrum. Specifically, for the visible LEDs, the semiconductor materials are required to be direct, as mentioned in the previous slide, with a band gap energy between 1.77 and 3.10 eV, seen here on
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This note was uploaded on 02/28/2012 for the course EE 4301 taught by Professor Laibowitz during the Spring '10 term at Columbia.

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