1. #1
    Unregistered

    Compare diffusion currents and Drift currents.

    Compare diffusion currents and Drift currents.
    thank you.




  2. #2
    ravikannth2027
    Join Date
    Jan 2012
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    hyderabad
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    Re: Compare diffusion currents and Drift currents.

    Diffusion Current :

    It is possible for an electric current to flow in a semiconductor even in the absence of the applied voltage provided a concentration gradient exists in the material

    Drift Current :

    When an Electric filed is applied across the semiconductor material , the charge carries attain a certain rift velocity Vd, which is equal to the product of the mobility of the charge carries & the applied Electric Field intensity E
    Drift Current due to the charge carriers such as free electronics & Holes are the current Passing through a square centimeter perpendicular to the direction of folw
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  3. #3
    GOUSEMOODHIN
    Join Date
    Jul 2012
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    188

    Re: Compare diffusion currents and Drift currents.

    ITS EASY FRIEND-
    *DIFFUSION CURRENT IN SEMICONDUCTOR CAUSED DUE TO DIFFUSION OF CHARGES (HOLES OR ELECTRONS)IT IS OPPOSITE TO DRIFT CURRENT.
    *DRIFT CURRENT IS FORMED BY ELECTRIC FIELD IN SEMICONDUCTOR.

  4. #4
    pavanipriya
    Join Date
    Jun 2012
    Posts
    31

    Re: Compare diffusion currents and Drift currents.

    Dear friend,

    Drift current:-
    Drift current is defined as the flow of electric current due to the motion of the charge carriers under the influence of an external electric field.
    Drift current due to the charge carriers such as free electrons and holes are the current passing through a square centimeter perpendicular to the direction of flow.
    Diffusion current:-

    It is possible for an electric current to flow in a semiconductor even in the absence of the applied voltage provided a concentration gradient exists in the material.
    A concentration gradient exists if the number of either elements or holes is greater in one region of a semiconductor as compared to the rest of the Region.
    In a semiconductor material the change carriers have the tendency to move from the region of higher concentration to that of lower concentration of the same type of charge carriers. Thus the movement of charge carriers takes place resulting in a current called diffusion current.

  5. #5
    ASHWANI SINGH
    Join Date
    Jul 2012
    Posts
    211

    Re: Compare diffusion currents and Drift currents.

    hi friend,
    drift and diffusion current are the two components that flows through the semiconductor material.the basic differences between them are:-
    1.drift current depends on the electric field applied ,if there is no electric field then no drift current occurs.but diffusion current occurs even though there is no electric field applied to the semiconductor.
    2.the other difference is that the direction of diffusion current depends on the change in the carrier concentration not the concentration themselves.

  6. #6
    pabolu manikanta
    Join Date
    Sep 2011
    Posts
    2,326

    Re: Compare diffusion currents and Drift currents.

    Hello Dude.........

    Generally the Current is of two types and these two current are
    *Drift Current
    *Diffusion Currents
    The Flow of Charged Particles or the Current through the semi conductors are of two types and these are known as the Drift Currents and the Diffusion Currents.

    Drift Current:
    When the electric Fields is applied across the semi conductor material then the charge carriers attain the certain drift velocity known as the drift current and this Drift velocity is represented as the
    Vd=mobility of charge carriers applied.......
    The Holes moves towards the negative terminal of the battery and the electrons moves towards the Positive terminal of the battery.......
    This Combined Effect is known as the Drift Current and this defined as the flow of electric Current due to the flow of electric current due to the motion of the charge carriers under the influence of these external electric fields.............
    This known as the drift Current..........
    Jn=q n un EA /cm2
    This is due to free electrons and due to holes are
    Jp=q p up EA/cm2

    Diffusion Current-
    It is possible for an electric current to flow in a semi conductor even in the absence applied voltage also provided a concentration gradient exists in the medium.This medium exists only if the number of either the holes or the electrons increases in one region.
    In the semi conductor materials the charge carriers have the tendency to move from high regions to low regions and thus this makes the Current flow and this current is known as the Diffusion currents.........

    REGARDS:

  7. #7
    jericho
    Join Date
    Apr 2012
    Location
    Bikaner, Rajasthan
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    1,246

    Re: Compare diffusion currents and Drift currents.

    Friend,

    Diffusion Current ::

    Diffusion current is a current in a semiconductor caused by the diffusion of charge carriers (holes and/or electrons).
    Diffusion current can be in the same or opposite direction of a drift current, that is formed due to the electric field in the semiconductor.
    Diffusion Current is Mainly Used in p-n Junction. It depends on constants Dp and Dn, and +q and −q, for holes and electrons respectively but it is independent of permittivity.
    Direction of the diffusion current depends on the change in the carrier concentrations, not the concentrations themselves.



    Drift Current ::

    Drift current is the electric current, or movement of charge carriers, which is due to the applied electric field, often stated as the electromotive force over a given distance.
    When an electric field is applied across a semiconductor material, a current is produced due to flow of charge carriers.
    It depends upon permittivity. Direction of the drift current depends on the polarity of the applied field.
    Drift current depends on the electric field applied on the p-n junction diode.



    Drift-Diffusion Equation :


    Good Luck.............

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