Hall Effect in p-Germanium
Names: Mr J.C Mosiea, Mr Ali, Mr K.G Tshabalala
Corresponding author: 2010085542@ufs4life.ac.za
Branding name: Physics Department, The University of the Free State, Private Bag X13, Phuthaditjhaba, 9866
Abstract
When a magnetic induction is introduced to a system existing of current, voltage and Hall voltage at specific temperatures, the relationships of these are altered as one factor is compared with the other for a given semi-conductor. There is an inverse relationship between the hall voltage and the current, for which the hall voltage is different from the normal voltage that is known. In this experiment, the aim is to determine the hall coefficients of germanium. Keywords Hall Effect Hall voltage Current…show more content… Current consists of movement of many small charge carriers, electrons, holes, ions or all three. When a magnetic field is present that is not parallel to the direction of motion of moving charges, these charges experience a force, called the Lorentz force. When such a magnetic field is absent, the charges follow approximately straight, 'line of sight' paths between collisions with impurities, phonons, etc. However, when a magnetic field with a perpendicular component is applied, their paths between collisions are curved so that moving charges accumulate on one face of the material. This leaves equal and opposite charges exposed on the other face, where there is a scarcity of mobile charges. The result is an asymmetric distribution of charge density across the Hall element that is perpendicular to both 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, so a steady electrical potential is established for as long as the charge is…show more content… For Task 5, the current was set to 30 mA and the magnetic induction to 300 mT. Using the temperature mode on the display, the following experimental findings of hall voltage as a function of temperature was collected:
Table 5: Table of Hall voltage as a function of temperature
Temperature (T) Hall voltage 〖(U〗_H)
25 0.9
35 0.91
45 0.91
55 0.87
65 0.82
75 0.69
85 0.48
95 0.26
105 0.1
115 0.02
125 -0.01
Graph 5: Hall voltage as a function of temperature
Calculations
Cross sectional area (Ge)=L x B =(10x〖10〗^(-3) m)(1x〖10〗^(-3) m) =1 x 〖10〗^(-5)