For an intrinsic semiconductor ($n_h$ and $n_e$ are the number of holes per unit volume and number of electrons per unit volume respectively)
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Logic Tip: In "intrinsic" (pure) semiconductors, balance is perfect ($n_e = n_h$). Extrinsic doping breaks this balance: N-type has excess electrons ($n_e>n_h$) due to donor impurities, and P-type has excess holes ($n_h>n_e$) due to acceptor impurities.