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| Numerical 01 |
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| In an intrinsic semiconductor, the energy gap Eg is 1 eV. Its hole mobility is very much smaller than electron mobility and is independent of temperature. What is the ratio between conductivity at 600 K and that at 300 K? Assume that the temperature dependence of intrinsic carrier concentration ni is expressed as |
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| ni = no exp [ -Eg/2kT], |
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| where no is a constant and k is Boltzmann constant [=8.62 x 10-5 eV/K] |
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| Suggested answer: |
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| It is given that me >> mh |
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| ne = nh = ni, for intrinsic semiconductor |
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| and s = no e me . exp[-Eg/2kT] |
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| = so exp [-Eg/2kT] [so=noeme = constant] |
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