Question 225: Semiconductors and Logic Gates

Question

In a semiconductor, the number density of intrinsic charge carries at 27$$^\circ$$C is 1.5 $$	imes$$ 1016/m3. If the semiconductor is doped with impurity atom, the hole density increases to 4.5 $$	imes$$ 1022/m3. The electron density in the doped semiconductor is ___________ $$	imes$$ 109/m3.

Accepted Answer

$${n_e}{n_h} = {n_i}^2$$
$${n_e} = {{{n_i}^2} \over {{n_h}}} = {{{{(1.5 	imes {{10}^{16}})}^2}} \over {4.5 	imes {{10}^{22}}}}$$
$$ = {{1.5 	imes 1.5 	imes {{10}^{32}}} \over {4.5 	imes {{10}^{22}}}}$$
$$ = 5 	imes {10^9}$$/m
3

Semiconductors and Logic Gates

In a semiconductor, the number density of intrinsic charge carries at 27$^\circC is 1.5 \times 1016/m3. If the semiconductor is doped with impurity atom, the hole density increases to 4.5 \times 1022/m3. The electron density in the doped semiconductor is ___________ \times$ 109/m3.

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