# Hall Effect Applications of Hall Effect

As a result, there is a voltage developed across these two sides of the semiconductor material as show by pink lines in the Figure 1b. The voltage so developed is called Hall Voltage (V_{H}) and the associated phenomenon is referred to as Hall Effect.
Moreover, the direction of the Hall voltage so developed will be perpendicular to both the direction of current flow as well as to the applied magnetic field. Thus, the **Hall effect** can be stated as the phenomenon where the current carrying conductor or semiconductor subjected to the external magnetic field develops a voltage across its terminals in the direction perpendicular to both the flow of current as well as to the direction of applied magnetic field.
Mathematical expression for the Hall voltage is given by
Where,
I represents current flowing through the sample
B represents the strength of the magnetic field
q represents the charge
n is the number of mobile charge carriers per unit volume
d represents the thickness of the sample
Here the term 1/(qn) is called the Hall Coefficient (R_{H}) and is negative if the majority charge carriers are electrons while positive if the majority charge carriers are holes.
**Hall effect** is a very useful phenomenon and helps to
Determine the Type of Semiconductor
By knowing the direction of the Hall Voltage, one can determine that the given sample is whether n-type semiconductor or p-type semiconductor. This is because Hall coefficient is negative for n-type semiconductor while the same is positive in the case of p-type semiconductor.

Calculate the Carrier Concentration
The expressions for the carrier concentrations of electrons (n) and holes (p) in terms of Hall coefficient are given by
Determine the Mobility (Hall Mobility)
Mobility expression for the electrons (μ_{n}) and the holes (μ_{p}), expressed in terms of Hall coefficient is given by,
where σ_{n} and σ_{p} represent the conductivity due to the electrons and the holes, respectively.
Measure Magnetic Flux Density
This equation can be readily deduced from the equation of Hall voltage and is given by
Further, there are many commercially available equipments based on the principle of Hall effect including Hall-effect sensors and Hall-effect probes.