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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.

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(a) The impurity provides impurity levels close to the conduction band and a number of electrons form the impurity level will populate the conduction band. Thus,the majority carriers are electrons and the meterial is n-type.
9According to the question,`kT=30meV`
or,`T=(30meV)/(k)`
`=0.03eV/8.62xx10^(-5)eVK_(-1)=348K.`
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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 .

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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

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