Principle

The resistivity and Hall voltage of 2  rectangular germanium samples ( n- and p-) are measured as a function of temperature and magnetic field.
The band spacing, the specific conductivity, the type of charge carrier and the mobility of the charge carriers are determined from the measurements.

Tasks

1. The Hall voltage is measured at room temperature and constant magnetic field as a function of the control current and plotted on a graph (measurement without compensation for defect voltage).
2. The voltage across the sample is measured at room temperature and constant control current as a function of the magnetic induction B.
3. The voltage across the sample is measured at constant control current as a function of the temperature. The band spacing of germanium is calculated from the measurements.
4. The Hall voltage UH is measured as a function of the magnetic induction B, at room temperature. The sign of the charge carriers and the Hall constant RH together with the Hall mobility mH and the carrier concentration p are calculated from the measurements.
5. The Hall voltage UH is measured as a function of temperature at constant magnetic induction B and the values are plotted on a graph.

Learning objectives

• Semiconductor
• Band theory
• Forbidden zone
• Intrinsic conductivity
• Extrinsic conductivity
• Valence band
• Conduction band
• Lorentz force
• Magnetic resistance
• Mobility
• Conductivity
• Band spacing
• Hall coefficient