The Photoconductivity Experiment Complete Set Up is designed for advanced physics laboratories to study the photoconductive properties of semiconductor materials using a CdS photoresistor. The experiment demonstrates the photoelectric effect by generating electron-hole pairs when light is incident on the semiconductor. Students investigate the relationship between light intensity, applied voltage, and photocurrent while gaining a practical understanding of semiconductor physics.
Objectives :
- Study the photoconductivity characteristics of a CdS photoresistor
- Measure the relationship between applied voltage and photocurrent at constant irradiance
- Investigate the variation of photocurrent with irradiance at constant applied voltage
- Understand the photoelectric effect in semiconductors
- Analyze the influence of light intensity on electrical conductivity
Principle :
- Photoconductivity occurs when incident light excites electrons across the energy band gap of a semiconductor into the conduction band, increasing the number of free charge carriers and thereby increasing its electrical conductivity. In this experiment, the CdS photoresistor is illuminated with white light, while the light intensity is precisely controlled using two crossed polarizing filters.
Experiments :
- Study of photoconductivity in a CdS photoresistor
- Applied voltage versus photocurrent at constant irradiance
- Photocurrent versus irradiance at constant applied voltage
- Light intensity variation using crossed polarizers
- Semiconductor conductivity analysis
- Photoelectric effect investigation
Educational Objectives :
- Understand the principles of photoconductivity
- Study the photoelectric effect in semiconductors
- Analyze the relationship between light intensity and electrical conductivity
- Measure photocurrent under different operating conditions
- Develop practical skills in optical alignment and electrical measurements
- Gain hands-on experience with semiconductor characterization experiments
- Understand the operation of photoresistors and optoelectronic devices
