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Translate the text “Laser Diodes. Theory of Operation” with a dictionary in writing and compare the operation of a semiconductor junction diode with that of a laser diode.

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  1. A GUIDELINES FOR WRITING
  2. A) What do these people want others to do for them? Fill in the table. Remember that The Complex Object is translated into Russian beginning with words чтобы, что, как.
  3. Act as an interpreter. Translate the description of N-type and P-type- semiconductors given by your group mates from English into Russian.
  4. Analyse the following examples and translate them.
  5. Change the complex sentences given below according to the examples and translate them into Russian.
  6. CREATIVE WRITING
  7. Ex. 12. Translate the text “Brain” into Ukrainian.
  8. Exercise 10. Translate into English. Check yourself by the key.
  9. Exercise 2. Translate the sentences into Ukrainian, paying attention to Complex Subject.
  10. INTERACTION OF PRIMARY DICTIONARY AND CONTEXTUALLY IMPOSED MEANINGS

A laser diode, like many other semiconductor devices, is formed by doping a very thin layer on the surface of a crystal wafer. The crystal is doped to produce an n-type region and a p-type region, one above the other, resulting in a p-n junction, or diode.

Laser diodes form a subset of the larger classification of semiconductor p-n junction diodes. As with any semiconductor p-n junction diode, forward electrical bias causes the two species of charge carrier – holes and electrons – to be "injected" from opposite sides of the p-n junction into the depletion region, situated at its heart. Holes are injected from the p-doped, and electrons from the n-doped, semiconductor. (A depletion region devoid of any charge carriers is formed automatically and unavoidably as a result of the difference in chemical potential between n- and p-type semiconductors wherever they are in physical contact.)

As charge injection is a distinguishing feature of diode lasers as compared to all other lasers, diode lasers are traditionally and more formally called "injection lasers." When an electron and a hole are present in the same region, they may recombine or "annihilate" with the result being spontaneous emission — i.e., the electron may re-occupy the energy state of the hole, emitting a photon with energy equal to the difference between the electron and hole states involved. Spontaneous emission is necessary to initiate laser oscillation, but it is one among several sources of inefficiency once the laser is oscillating.

 

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