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Measurement of the Electrical Properties of Semiconductors by Van Der Pauw…
Measurement of the Electrical Properties of Semiconductors by Van Der Pauw and Hall Effect methods.
THEORY
Semiconductor material >> materials which have electrical conductivity in between of a conductor.
Van der Pauw Method
>> a technique commonly used to measure the resistivity and the Hall coefficient of a sample.
Hall Effect
>> the movement of charge carriers through a conductor towards a magnetic attraction.
METHODS
Van der Pauw Method
Sample given is sketched and contacts 1,2,3 and 4 are designated on the sample.
The four corners are carefully clipped with crocodile clips.
Current is applied to contacts 1 and 2 and the voltage produced at contacts 3 and 4 are being recorded.
The current is increased to obtain ten different readings.
RA and RB is then calculated by given formula.
Thickness of the sample, d is measured by a micrometer
The resistivity of the material is calculated.
Hall Effect
Sheet resistance, hall voltage, hall coefficient, carrier density and carrier mobility are observed and recorded.
Sample cards with semiconductors is attached to the smart card and is being focused.
WHAT I'VE LEARNT
The sheet resistance decreases as follows : Silicon Wafer > InAs > TiO2
The carrier density decreases as follows : InAs > Silicon > TiO2
The carrier mobility decreases as follows : InAs > TiO2 > Silicon
IMPORTANCE
InAs and TiO2 is n-type semiconductor as electrons is their major charge carrier while Silicon wafer is p-type with hole as major charge carrier. Higher carrier density and mobility will results in higher conductivity in semiconductor
