Electrical Mobility Calculator

What Is Electrical Mobility?

Electrical mobility $\mu$ measures how fast charge carriers drift per unit electric field. It is central to semiconductor device physics, Hall effect measurements, and transistor design.

Mobility Formula

$$\mu = \frac{v_d}{E}$$

$v_d$ is drift velocity in m/s and $E$ is electric field strength in V/m. SI units for mobility are m²/(V·s). In semiconductor literature, values are often quoted in cm²/(V·s); multiply by 10⁴ to convert.

Example: electrons drifting at 100 m/s in a 1000 V/m field have $\mu = 0.1$ m²/(V·s), or 1000 cm²/(V·s).

Typical Mobilities

Silicon electron mobility at room temperature is about 1400 cm²/(V·s). Hole mobility is about 450 cm²/(V·s). Mobility decreases at high doping and high temperature due to increased scattering.

Frequently Asked Questions

What is drift velocity?

Drift velocity is the average velocity of charge carriers moving under an electric field, distinct from their much faster random thermal motion.

How do I convert cm²/(V·s) to m²/(V·s)?

Divide by 10⁴. For example, 1400 cm²/(V·s) equals 0.14 m²/(V·s).

What affects carrier mobility?

Temperature, doping concentration, crystal quality, and the type of scattering (phonon, impurity, surface) all affect mobility.

Is mobility the same for electrons and holes?

No. Electrons generally have higher mobility than holes in most semiconductors because of their lighter effective mass.

How is mobility measured experimentally?

Hall effect measurements and time-of-flight techniques are common methods to determine carrier mobility in materials.

Report

What Is Electrical Mobility?

Mobility Formula

Typical Mobilities

Frequently Asked Questions

Related Tools

Recent Visits

Finance Calc Kit