Hall effect can be used to measure

Hall Voltage states that if a specimen (metal or semiconductor) carrying a current I is placed in transverse magnetic field B, an electric field is induced in the direction perpendicular to both I and B.

Hall Voltage is given by:

\({V_H} = Ed = \frac{{BI}}{{ρ W}}\)

ρ = Charge density

Hall coefficient can be written as:

\({{\rm{R}}_{\rm{H}}} = \frac{1}{{\rm{ρ }}} = \frac{1}{{{\rm{ne}}}}\)

Where,

ρ = charge density = σ / μ 

n = charge concentration

σ = conductivity

μ = mobility constant

Hence, the Hall coefficient becomes

\({{\rm{R}}_{\rm{H}}} = \frac{1}{{\rm{ne }}} = \frac{\mu}{{{\rm{\sigma }}}}\)

The Hall effect provides information on the sign, concentration, and mobility of charge carriers in the normal state.

A positive sign for the Hall coefficient indicates that the majority carriers are holes and the semiconductor is P-type.

A negative sign for the Hall coefficient indicates that the majority carriers are electrons and the semiconductor is N-type.

Applications of Hall-effect:

Hall effect can be used to find:

1. Carrier concentration

2. Type of semiconductor

3. Conductivity

4. Mobility

It cannot be used to find a magnetic field.

Common Confusion Point:

Looking at the formula one can think that the magnetic field can be calculated but in the HALL Experiment, perpendicular MAGNETIC field and electric field are applied on the material and other parameters are measured.