This is the environment
Aim of The Experiment
To Study temperature dependence of resistivity in germanium (Ge) and to estimate the electronic band gap (Eg) energy in Germanium (Ge) using Four-point probe setup with furnace.
Introduction
Read the Introduction from the Manual
Demo Video 1
Courtesy: Amrita University
Demo Video 2
Courtesy: IIT Bhubaneswar
Apparatus Required
Click on the following apparatus to see them.
Available Sample
- Germanium
- Silicon
Procedure
Click on step buttons to continue following the procedure.
Step 1
Put the sample on the base plate of the four probe arrangement. Unscrew the pipe holding the four probes and let the four probes rest in the middle of the sample. Apply a very gentle pressure on the probes and tighten the pipe in this position. Check the continuity between the probes for proper electrical contacts.
Caution: The Ge crystal is very brittle. Therefore, use only the minimum pressure required for proper electrical contacts. The resistance between the Red and Black probes and Yellow and Green probe may be approximately few K-Ohms (~1-4 K-Ohms).
Step 2
Connect the outer pair of probes (red/black) leads to the constant current power supply and the inner pair (yellow/green leads) to the probe voltage terminals.
Step 3
Place the four probe arrangement in the oven and fix the thermometer in the oven through the hole provided.
Step 4
Switch on the ac mains of Four Probe Set-up and put the digital panel meter in the current measuring mode through the selector switch. In this position LED facing mA would glow. Adjust the current to a desired value
Step 5
Switch on the ac mains of Four Probe Set-up and put the digital panel meter in the current measuring mode through the selector switch. In this position LED facing mA would glow. Adjust the current to a desired value
Step 6
Please set the parameters in the following fields.
Step 7
Use the following buttons to generate the experimental data. If the values are not given in step 6, then default values will be used.
Step 8
Result
Note down the values of voltage and temperature from step 8 of procedure. Calculate the resistivity following the method presented in the manual. Obtain a plot of natural logarithm of resistivity versus inverse of temperature. Calculate the bandgap of the material from the slope of the plot.
Discussion
Discuss your findings in your report.
Conclusion
Conclude the result obtained from the experiment. Mention the things you learnt fromt the experiment. Write the precaution to take while performing the actual experiment in laboratory. Give suggestion to improve the experiment.