Hello!

Let us understand the structure of semiconductor laser.

Construction :

• In semiconductor laser there are two types, n-type and p-type.

• The n-type consists of holes as majority charge carriers and the p-type consists of electrons as majority charge carriers.

• The n-section is formed by doping with tellurium.

• The p-section is formed by doping with zinc.

• The doping concentration is very high and is of order 10^7 to 10^9 dopant atom per cm^3.

• The overall size of laser diode is very small having each of its size of 1mm.

• The width of the laser diode is varying from 1μm to 100μm, depending upon diffusion and temperature conditions.

• The parallel faces of the junction are roughened ends and at other parallel faces one is polished end and one is partially polished end.

• There is a depletion region where holes and electrons are attracted, resulting to give LED (light).
  The depletion layer is also called as population inversion.