Equilibrium semiconductor carrier densities
In nondegenerate three-dimensional parabolic bands, n=N_c exp[−(E_c−μ)/(k_BT)] and p=N_v exp[−(μ−E_v)/(k_BT)], where N_c,v=2(2πm_c,v*k_BT/h²)³ᐟ² for one isotropic valley including two spins.
Key knowledge
In nondegenerate three-dimensional parabolic bands, n=N_c exp[−(E_c−μ)/(k_BT)] and p=N_v exp[−(μ−E_v)/(k_BT)], where N_c,v=2(2πm_c,v*k_BT/h²)³ᐟ² for one isotropic valley including two spins. Thus np=N_cN_v exp[−E_g/(k_BT)]=n_i². Charge neutrality gives n+N_A⁻=p+N_D⁺; intrinsic material has n=p=n_i.
Values and equations
n=N_c e^[−(E_c−μ)/(k_BT)]; p=N_v e^[−(μ−E_v)/(k_BT)]; np=n_i²; n+N_A⁻=p+N_D⁺
- n,p,n_i,N_c,N_v,N_A⁻,N_D⁺
- Carrier/intrinsic/effective-state/ionized-dopant number densities m⁻³
- E_c,E_v,E_g,μ
- Band edges, gap and equilibrium chemical potential J
- k_B
- Boltzmann constant J K⁻¹
- T
- Temperature K
- m_c,v*
- Isotropic density-of-states effective masses kg
- h
- Planck constant J s
Conditions and scope
- Thermal equilibrium with one chemical potential, T>0, dilute Boltzmann band populations, fixed material band gap E_g=E_c−E_v>0 and the displayed parabolic density-of-states approximation.
- Valley degeneracy and anisotropic density-of-states masses modify N_c,N_v. Ionized dopant densities must be evaluated; freeze-out, degeneracy or nonequilibrium injection invalidate simplified full-ionization/Boltzmann inferences. Intrinsic μ need not be exactly mid-gap at finite T.
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): §16.3 equations 16.6–16.9 and Intrinsic/Doped Semiconductors: Boltzmann densities, mass-action product and neutrality; h=2πħ rewrites prefactors. Uses ionized dopants rather than the source's high-temperature fully activated special case. Excludes wrong g_v label in the conduction integral, the Gaussian-derivative minus-sign slip and incorrect hole-integral algebra.
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.
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