Device physicsMVP
Mobility / conductivity explorer
How conductivity scales with carrier concentration and mobility, σ = q·n·μ (single carrier).
Inputs
Single-carrier, constant-mobility model
σ = q·n·μ for one carrier type with mobility treated as constant. Real mobility falls at high doping and high field; this is an educational linear relationship.
Conductivity
2.243 S/cm
224.3 S/m · ρ = 0.4458 Ω·cm
Interpretation
Conductivity is the product of charge, carrier concentration, and mobility (σ = q·n·μ). Doping raises n and thus σ; mobility sets how freely those carriers move. Because electrons are usually more mobile than holes, n-type material of the same doping conducts somewhat better. In reality mobility itself drops at very high doping, so σ rises less than linearly there.
Formula
σ = q · n · μ
q = elementary charge.
Variables
| Symbol | Variable | Unit |
|---|---|---|
| σ | Conductivity | S/m (shown as S/cm) |
| n | Carrier concentration | m⁻³ |
| μ | Carrier mobility | m²/(V·s) |
Assumptions & validity
This tool assumes:
- Single carrier type; constant mobility.
- Ignores high-doping and high-field mobility degradation.
Worked example
n = 1×10¹⁶ cm⁻³, μ = 1400 cm²/(V·s).
σ = q·n·μ ≈ 0.22 S/m (≈ 0.0022 S/cm)