Intrinsic carrier concentration of Si at 300 K is approximately:

n_i for Si ≈ 1.5 × 10¹⁰ /cm³ = 1.5 × 10¹⁶ /m³. **Strongly T-dependent:** exp(-E_g/2kT). Far below metal carrier density (~10²⁸/m³), which is why Si is much less conductive than copper.