Hall Effect
INTRODUCTION
If an electric current flows through a conductor in a magnetic field, the magnetic field exerts a transverse force on the moving charge carrier which tends to push them to one side of the conductor. A buildup of charge at the sides of the conductors will balance this magnetic influence, producing a measurable voltage between the two sides of the conductor. This presence of measurable transverse voltage is the Hall Effect. The Hall effect was discovered in 1879 by Edwin Herbert Hall while working on his doctoral degree at the Johns Hopkins University. The Hall effect is due to the nature of current in a conductor. Current consists of the movement of many small carriers(electrons, holes or both). Moving charges experience the Lorentz force when a magnetic field is present that is perpendicular to their motion. In the absence of the magnetic field, the charges follow ‘line of sight’ paths between collisions with impurities. On the other hand, when a perpendicular magnetic field is present, their paths are curved and moving charges accumulate on one face of the material. Equal and opposite charges are exposed on the other face, where there is a scarcity of mobile charges. The result is an asymmetric distribution of charge density across the element that is perpendicular to the ‘line of sight’ path and the applied magnetic field. The separation of charge establishes an electric field that opposes the migration of further charge, and a steady electrical charge builds up while the current is flowing. The Hall effect offered the first proof that electric currents in metals are carried by moving electrons. The effect is very useful in measuring either the carrier density or the magnetic field.
HALL EFFECT IN SEMICONDUCTORS
A static magnetic field has no effect on a charged particle unless it is moving. When charges flow, a mutually perpendicular force (Lorentz force) is induced on the charge.[1] A Hall voltage Vhall will measured perpendicular to B and
If an electric current flows through a conductor in a magnetic field, the magnetic field exerts a transverse force on the moving charge carrier which tends to push them to one side of the conductor. A buildup of charge at the sides of the conductors will balance this magnetic influence, producing a measurable voltage between the two sides of the conductor. This presence of measurable transverse voltage is the Hall Effect. The Hall effect was discovered in 1879 by Edwin Herbert Hall while working on his doctoral degree at the Johns Hopkins University. The Hall effect is due to the nature of current in a conductor. Current consists of the movement of many small carriers(electrons, holes or both). Moving charges experience the Lorentz force when a magnetic field is present that is perpendicular to their motion. In the absence of the magnetic field, the charges follow ‘line of sight’ paths between collisions with impurities. On the other hand, when a perpendicular magnetic field is present, their paths are curved and moving charges accumulate on one face of the material. Equal and opposite charges are exposed on the other face, where there is a scarcity of mobile charges. The result is an asymmetric distribution of charge density across the element that is perpendicular to the ‘line of sight’ path and the applied magnetic field. The separation of charge establishes an electric field that opposes the migration of further charge, and a steady electrical charge builds up while the current is flowing. The Hall effect offered the first proof that electric currents in metals are carried by moving electrons. The effect is very useful in measuring either the carrier density or the magnetic field.
HALL EFFECT IN SEMICONDUCTORS
A static magnetic field has no effect on a charged particle unless it is moving. When charges flow, a mutually perpendicular force (Lorentz force) is induced on the charge.[1] A Hall voltage Vhall will measured perpendicular to B and
References: [1] Prof H.E.M. Barlow , The Application Of The Hall Effect In A Semiconductor Measurement Of Power In An Electromagnetic, 1963, vol 110 , page 79-84 [2] D. Silverman , Industrial Applications of Hall-Effect Devices [3] Ryo Shimano, Terahertz Magneto-Optics of Quantum Hall Effect and Anomalous Hall effect, 2011 [4] Viktor A Pogrebnyak, Electron Standing Wave Resonances in 2-D Quantum Well And Fractional Quantum Hall Effect , 1998, vol 2, page 719-721 [5] Bowei Zhang, High Sensitive Circular Hall Effect for Magnetic Bead Immunoassay, 2010 , [6] G. Gokmen , K. Tuncalp, The Design of a Hall Effect Current Transformer and Examination of the linearity with Real time Parameter Estimation, 2010 [7] Predag Pejovic , Dragan Stankovic, Current Analysis of Compensated Hall-Effect Current Transducers, Vol 2, 1997 [8] Antonio Cataliotti, Dario Di Cara, Salvatore Nuccio, Hall Effect Current Transducer Characterization Under Nonsinusoidal Conditions, 2009