Measurement of the Electrical Properties of Semiconductors by Van Der Pauw and Hall Effect methods.
THEORY
METHODS
WHAT I'VE LEARNT
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.
Van der Pauw Method
Hall Effect
- 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.
- 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.
IMPORTANCE
- 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.
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
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