The intrinsic carrier density at $300 \mathrm{~K}$ is $1.5 \times 10^{10}$ / $\mathrm{cm}^{3}$, in silicon. For $n$-type silicon doped to $2.25 \times$ $10^{15}$ atoms $/ \mathrm{cm}^{3}$, the equilibrium electron and hole densities are
- $n=1.5 \times 10^{15} / \mathrm{cm}^{3}, p=1.5 \times 10^{10} / \mathrm{cm}^{3}$
- $n=1.5 \times 10^{10} / \mathrm{cm}^{3}, p=2.25 \times 10^{15} / \mathrm{cm}^{3}$
- $n=2.25 \times 10^{15} / \mathrm{cm}^{3}, p=1.0 \times 10^{5} / \mathrm{cm}^{3}$
- $n=1.5 \times 10^{10} / \mathrm{cm}^{3}, p=1.5 \times 10^{10} / \mathrm{cm}^{3}$