Electron–hole mobility and conductivity
At weak electric field in a two-carrier relaxation-time band model, v_n=−μ_nE and v_p=+μ_pE with positive mobilities μ=|e|τ/m*.
Key knowledge
At weak electric field in a two-carrier relaxation-time band model, v_n=−μ_nE and v_p=+μ_pE with positive mobilities μ=|e|τ/m*. Conventional charge currents add, so j=e(nμ_n+pμ_p)E and σ=e(nμ_n+pμ_p). A high carrier density does not alone fix conductivity without mobilities.
Values and equations
μ_n,p=eτ_n,p/m_n,p*; σ=e(nμ_n+pμ_p); j=σE
- μ_n,μ_p
- Positive electron/hole mobility m² V⁻¹ s⁻¹
- e
- Positive elementary-charge magnitude C
- τ_n,τ_p
- Relaxation times s
- m_n*,m_p*
- Carrier effective masses kg
- n,p
- Mobile electron/hole number densities m⁻³
- σ
- Conductivity S m⁻¹
- j
- Conventional current density A m⁻²
- E
- Applied electric field V m⁻¹
Conditions and scope
- Locally isotropic parabolic bands with positive carrier masses, linear stationary low-field response, specified temperature/composition and relaxation times; no simultaneous magnetic-field deflection in this scalar law.
- Scattering depends on material/conditions; high-field velocity saturation, anisotropic tensors and multiple bands require their own transport models.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Solid State Physics: third-year lecture notes (2012): §16.1.1 Drude Transport: Redux: displayed electron/hole force-relaxation equations; equilibrium force balance gives positive mobility and charge-current sum. Excludes printed μ=|E|/|v|, which is inverted; correct μ=|v|/|E|.
2026-10-10 · Independent AI editorial review: All 136 unique authored Physics compact statements, all hypotheses and displayed equations/variable/units tables, all 192 Physics-origin semantic links, exact 165 author inspection matrix and mapped retained conceptual claims have been independently read. Three Physics-tagged Measurement realization records are delegated to root Measurement review. Scientific source verification combines exact author section inspection with independent whole compact-content/semantic review and targeted primary rechecks recorded below; it does not claim each full source body was independently reread. Independent AI editorial review is not human specialist certification or experimental replication. Field inventory is approved after independently reviewing the two added source-inspected band-construction methods. Receipt: physics-independent-content-inventory-review.1.
Entry details
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- physics-semiconductor-mobility-conduction
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