(adsbygoogle = window.adsbygoogle || []).push({}); Why n*p always equal to ni square?? (semiconductor)

Hi,

For you guys who studied semiconductor physics must be familiar with the equation:

np=n_{i}^{2}

I can understand why this is true for the intrinsic case (the broken bonds would always provide electron and hole in pairs )

But why is this still true for dopped semiconductors? Take Si for example, n=p=n_{i}=10^{10}in intrinsic case (that's we all know). However, if dope 10^{15}N_{d}into the material, then n~10^{15}and p~10^{5}. The highlighted part is my confusion! Why p become smaller? Where do the holes go?

Thanks for helping!

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# Why n*p always equal to ni square? (semiconductor)

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