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The impurity levels of a doped semiconductor are 30 me V below the conduction band. Determine whether the semiconductor is n-type or p-type. At the room temperature thermal collisons occur as a result of which the extra electron loosely bound to the impurity ion gets an amount of emergy kT [where k is Boltzmann constant =8.62xx10^(-5) eV//K] and hence this electron can jump into conduction band. What is the value of T? |
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Answer» Solution :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` |
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