Lecture on PN and PIN Photodiodes

Introduction

• Discussing article and communication in today's session.
• Focus on PN and PIN Photodiodes.

Working of PN Photodiode

• Converts optical light energy into electric current.
• Generates displacement current from photos.
• Works well in reverse bias mode similar to the concept in "Three Idiots" movie.
• Involves n-type and p-type semiconductors.
  • n-type connected to battery's positive terminal.
  • p-type connected to the negative terminal.
• Light falling on the depletion layer generates current.

Construction of PN Photodiode

• Involves a p-n junction with light exposure.
• n-type: positive terminal, should not behave in depletion condition.
• Photons generate electron-hole pairs.

Behavior under Illumination

• Generating electrons based on light exposure.
• Minority carriers' movement induced by diffusion process.
• Increasing thickness of junction enhances response speed

PIN Photodiode Details

• P-layer connects to negative, N-layer to positive.
• Heavily doped with group V elements.
• Central intrinsic layer enhances efficiency.

Performance Factors

• Type and concentration of doping influence behavior.
• Control over doping concentration to optimize response.
• Diffusion and depletion regions play crucial roles.
• Intrinsic layer smooths and enhances response under light.

Conclusion & Next Steps

• Follow-up on detailed working in next sessions.
• Understanding photodiodes and photodetectors critical for applications.

Final Notes

• Encouragement to like, subscribe, and share for more content.