Home
Class 12
PHYSICS
A doped semiconductor has impurity level...

A doped semiconductor has impurity levels 30meV bleow the conduction band,(a)Is the material m-type or p-type? (b)In a thermal collision,and amount kT of energy is given to the extra electron loosely bound to the impurity ion and this electron is just able to jump into the conduction band. Calculate the temperature T.

Text Solution

Verified by Experts

The separation of impurity energy level from conduction band is less in case of n-type semiconductor and more in case of p-type semiconductor. As energy separation of impurity level `=30xx10^(-3)eV` is much smaller than energy gap of pure semiconductor `(~~1eV)`, therefore, the doped semiconductor is n-type.
Here, `E_(g)=30xx10^(-3)eV=kT`
or `T=(30xx10^(-3))/k=(30xx10^(-3))/(8.62xx10^(-5))=348K`
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • ELECTRONIC DEVICES

    PRADEEP|Exercise MCQ|5 Videos

  • ELECTRONIC DEVICES

    PRADEEP|Exercise INTEGER TYPE QUESTION|2 Videos

  • ELECTRONIC DEVICES

    PRADEEP|Exercise LONG QUESTION ANSWER|2 Videos

  • ELECTROMAGNETIC WAVES

    PRADEEP|Exercise II Focus multiple choice question|5 Videos

  • ELECTROSTATICS

    PRADEEP|Exercise ASSERTION-REASON TYPE QUESTIONS|2 Videos

Similar Questions

Explore conceptually related problems

A doped semiconductor has impurity levels 40 me V below the conductor band. Is the material n-type or p-type? In a thermal collision, an amount kT of energy is given to the extra electron loosely bound to the impurity ion and this electron is just able to jump into the conduction band. Calculate the temperature T. Given k=8.62xx10^(-5) eV//K .

A doped semiconductor has impurity levels 30meV below the conduction band. Is the material n -type or p - type? Find the maximum wavelength of ight so that an electron of impurity level is just able to jump to into conduction band.

Knowledge Check

  • A doped semiconductor has impurity levels 32 meV below the conduction band. The semiconductor is -

    A
    N-type
    B
    P-type
    C
    N-P junction
    D
    none of the above

  • An n-type semiconductor has impurity level 20 meV below the conduction band. In a thermal collision, transferble enegry is KT . The value of T for which electrons start to jump in conduction bond is :

    A
    232 K
    B
    348 K
    C
    400 K
    D
    600 K

    • Similar Questions

    Explore conceptually related problems

    A doped semiconductor has impurity levels 20 meV below the conduction band. Is the material n-type or p-type? What is the wavelength of light so that the electron of impurity level is just able to jump into conduction band? Use h=6.63xx10^(-34)Js, c=3xx10^(8)m//s .

    Impurity levels in a doped semiconductor is found to be 35 millielectron volts below the conduction at temperature T_(1) when thermal collisions take place approximate amount of energy and reach the conduction band due to collisions then estimate the temperature of the sample

    in an n-type semiconductor, the donor energy level lies (a) at the center of the energy gap (b) just below the conduction band (c)just above the valence band (d) in the conduction band

    When a semiconducting meterial is doped with an impurity,new acceptor levels are created .In a particular thermal collision,a valence electrons recives an energy equal to 2kT and just reaches one of the acceptor levels. Assuming that the energy of the electron was at the top edge of hte valence band and that the temperature T is equal to 300K, find the energy of the acceptor levels above the valence band.

    When an electron goes fron the valence band to the conduction band in silicon,its energy is increased by 1.1eV.the average energy exchange in a thermal collision is of the order of kT which is only 0.026eV at room tempareture.How is a thermal collision able to take some of the electrons from the valence band to the conduction band ?

    A semiconducting material has a band gap if 1 eV.Acceptor impurities are doped into it which create acceptor level 1meV above the valence band.Assume that the transition form one energy level to the otheris almost forbidden if kT is less than 1//50 of the energy gap.Also,if kT is more than twice the gap, the upper levels have maximum polution.The temperature of the semiconductor is increaased form 0K.The concentration of the holes increase with temperature and after a certain temperature it becomes approximately constant.As the tamperature is further increased the hole concentration again starts increasing at certain temperature, Find the order of the temperature range in which the hoel concentration remains approximately constant.

    Home
    Profile