Chances are you’ve used a semiconductor laser in the last few days without even knowing it. If you’ve watched a DVD, you’ve “looked through” one; if you’ve been into a grocery store and had a barcoded product swiped through the checkout you’ve bought with one; if you’ve made a long-distance telephone call by fiber-optic cable you’ve “talked through” one; and if you’ve printed something with a laser printer your printout has passed very near one. Semiconductor lasers make powerful, precise beams of light (like ordinary lasers), but they’re about the same size as simple LEDs—the little-colored lamps you see on electronic instrument panels.
f you’ve read our article on diodes, you’ll already have an idea of how LEDs work. Essentially, an LED is a semiconductor sandwich with the “bread” made from slices of two different kinds of treated silicon known as p-type (rich in “holes” or, in other words, slightly lacking electrons, the tiny negatively charged particles inside atoms) and n-type(with slightly too many electrons). Put the two slices together and you make what’s called a p-n junction diode that has all kinds of interesting properties.
In an ordinary diode, the p-n junction works like a turnstile that allows electric current to flow in only one direction (known as forward-biased operation). As electrons flow across this barrier, they combine with holes on the other side and give out energy in the form of phonons (sound vibrations) that disappear into the silicon crystal. In an LED, much the same process takes place but the energy is given out not as phonons but as photons—packets of visible light.
To know More about semiconductor grab the chance and attend the forthcoming Conference: 5th International Conference on Advanced Material Research and Nanotechnology.
Dates of the Conference: May 22-23, 2019
Venue: Rome, Italy
For more Details: Advanced Materials 2019
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