Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Doubt in semiconductor diode theory ?

  1. Jun 7, 2010 #1
    doubt in semiconductor diode theory ????

    hello friends :smile:....

    in this picture diode is forward biased. positive terminal of battery repel holes n negative repel electrons , finaly electrons n holes recombine n eliminate each other.

    but its said that current flow is due to electrons . but electrons -holes both are eliminated. then how can we say that current flow is due to electrons.
    how can they come out of both terminals of battery as they are eliminated inside ....????

    please clarify my confusion....

    Attached Files:

  2. jcsd
  3. Jun 7, 2010 #2
    Re: doubt in semiconductor diode theory ????

    It is not like that. The current outside the diode terminals (i.e., in the wire) is due to flow of electrons only. But inside the diode, the holes actually did not move. It is the electron which move forward and leaves a hole in backward direction, so as the electron progresses, it appears that hole moves in opposite direction to that of electron. It is a steady state process in forward biased diode, since new electrons come in through N side and after passing through P it reaches the battery and completes its path.
  4. Jun 8, 2010 #3
    Re: doubt in semiconductor diode theory ????

    The "holes" (positive) don't move. Only the electrons move. Then the electrons jump to the battery leaving the "hole" for the next electron to jump into.
  5. Jun 8, 2010 #4
    Re: doubt in semiconductor diode theory ????

    oki understand now....i think hole is actually a vacancy for electron. it can not move....

    thanks friends.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook