TheAlgorithms/Python · error · ValueError

Intrinsic concentration cannot be negative in a semiconducto

Error message

Intrinsic concentration cannot be negative in a semiconductor

What it means

Thrown by carrier_concentration() when intrinsic_conc < 0 while exactly one argument is 0. The intrinsic (thermal equilibrium) carrier concentration ni is a positive material property (e.g. ~1e10 cm^-3 for silicon at 300 K); a negative value is non-physical and is rejected before ni^2 is used.

Source

Thrown at electronics/carrier_concentration.py:50

        ...
    ValueError: Electron concentration cannot be negative in a semiconductor
    >>> carrier_concentration(electron_conc=0, hole_conc=-400, intrinsic_conc=1200)
    Traceback (most recent call last):
        ...
    ValueError: Hole concentration cannot be negative in a semiconductor
    >>> carrier_concentration(electron_conc=0, hole_conc=400, intrinsic_conc=-1200)
    Traceback (most recent call last):
        ...
    ValueError: Intrinsic concentration cannot be negative in a semiconductor
    """
    if (electron_conc, hole_conc, intrinsic_conc).count(0) != 1:
        raise ValueError("You cannot supply more or less than 2 values")
    elif electron_conc < 0:
        raise ValueError("Electron concentration cannot be negative in a semiconductor")
    elif hole_conc < 0:
        raise ValueError("Hole concentration cannot be negative in a semiconductor")
    elif intrinsic_conc < 0:
        raise ValueError(
            "Intrinsic concentration cannot be negative in a semiconductor"
        )
    elif electron_conc == 0:
        return (
            "electron_conc",
            intrinsic_conc**2 / hole_conc,
        )
    elif hole_conc == 0:
        return (
            "hole_conc",
            intrinsic_conc**2 / electron_conc,
        )
    elif intrinsic_conc == 0:
        return (
            "intrinsic_conc",
            (electron_conc * hole_conc) ** 0.5,
        )
    else:

View on GitHub (pinned to f5988cc097)

Solutions

1. Supply a positive intrinsic concentration (use ni ≈ 1e10 cm^-3 for Si at 300 K if unsure).
2. If ni comes from a temperature model, validate the temperature range before computing it.
3. Treat negative ni as invalid input data and fail early in your own pipeline.

Example fix

# before
carrier_concentration(electron_conc=0, hole_conc=400, intrinsic_conc=-1200)

# after
carrier_concentration(electron_conc=0, hole_conc=400, intrinsic_conc=1200)

if intrinsic_conc <= 0:
    raise ValueError("intrinsic_conc must be positive (Si@300K ~ 1e10 cm^-3)")
result = carrier_concentration(electron_conc, hole_conc, intrinsic_conc)

When it happens

Trigger: carrier_concentration(electron_conc=0, hole_conc=400, intrinsic_conc=-1200) — exactly one zero but negative intrinsic concentration.

Common situations: Temperature-dependent ni lookups returning negative garbage on out-of-range temperatures; tabulated data with missing values encoded as negatives; manual entry typos.

Related errors

• Electron concentration cannot be negative in a semiconductor
• Hole concentration cannot be negative in a semiconductor
• Conductivity cannot be negative
• Electron concentration cannot be negative
• mobility cannot be negative

AI-assisted analysis of TheAlgorithms/Python@f5988cc097 (2026-08-14). Data as JSON: /api/errors/6b22267cba1575f6. Report an issue: GitHub.