Hall Effect definition
When magnetic field is applied to a current carrying conductor in a direction perpendicular to that of the flow of current, a potential difference or transverse electric field is created across a conductor. The potential difference created across the conductor due to the applications of magnetic field in a direction perpendicular to that of the flow of current is called Hall Effect.
Hall Effect was discovered by Edwin Hall in 1879. The voltage or electric field produced due to the application of magnetic field is also referred to as Hall voltage or Hall field.
What is Hall Effect?
We know that p-type semiconductor and n-type semiconductor are the two types of semiconductors.
In n-type semiconductor, free electrons are
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When magnetic field is applied to the current carrying conductor or semiconductor in a direction perpendicular to that of the flow of current, an electric field is produced in conductor in the direction perpendicular to both magnetic field and electric current. This phenomenon is known as Hall Effect. Hall Effect was named after American Physicist Edwin Hall, who discovered the phenomenon in 1879.
Consider a material, either a semiconductor or conductor as shown in the below figure. When voltage is applied, electric current starts flowing in the positive x direction (from left to right). If a magnetic field is applied to this current carrying conductor in a direction perpendicular to that of the flow of current (that is z direction), an electric field is produced in the conductor that exerts force in the negative y direction (downwards).
Hall Effect in conductor
This electric field pushes the charge carriers downwards. If the material is a conductor, the electric field pushes the free electrons downwards (negative y direction). As a result, a large number of charge carriers (free electrons) are accumulated at the bottom surface of the
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In n-type semiconductor, the electric field is primarily produced due to the negatively charged free electrons. So the hall voltage produced in n-type semiconductor is negative.
Hall Effect in p-type semiconductor
If the magnetic field is applied to a p-type semiconductor, the majority carriers (holes) and the minority carriers (free electrons) are pushed down towards bottom surface of the p-type semiconductor. In p-type semiconductor, free electrons are negligible. So the bottom surface of the p-type semiconductor is mostly accumulated with positive charge carriers (holes).
This produces a positive charge at bottom surface with an equal amount of negative charge at upper surface. So in p-type semiconductor, the bottom surface is positively charged and the upper surface is negatively charged.
As a result, potential difference is developed between the upper and bottom surface of the p-type semiconductor. In p-type semiconductor, the electric field is primarily produced due to the positively charged holes. So the hall voltage produced in p-type semiconductor is
Mottelay, F. P., (2013, November 20) Bibliographical History of Electricity and Magnetism, p. 114. retrieved from:http://en.wikipedia.org/wiki/Aurora_(astronomy)
Answer: It is the difference between interfacial conduction band edge (Ec) and the Fermi level (Ef). From the figure below we get a better idea of the barrier height which is given by ΦB(PhiB).
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