Q1. Attempt the following questions.
- (a)) Describe various electron-hole pair generation processes in semiconductor. (200 words)
- (b)) Explain the complete switching ON and OFF cycle of a power diode with the help of appropriate diagram. What are forward and reverse recovery times of a power diode? (200 words)
- (c)) How can the efficiency of a solar cell be increased? How is the optimum bandgap chosen for the solar cell material? (200 words)
Key Points:
- Thermal, optical, and impact ionization generate electron-hole pairs in semiconductors.
- Power diode turn-on involves depletion region collapse and carrier injection.
- Power diode turn-off exhibits reverse recovery current due to stored minority charge.
- Reverse recovery time (t_rr) quantifies the time for stored charge removal in diodes.
Answer: Semiconductors are fundamental to modern electronics, and understanding phenomena like electron-hole pair generation, diode switching characteristics, and solar cell efficiency is crucial. This answer will delve into these core concepts as typically covered in an electronics course, explaining the underlying physics and practical implications. Electron-hole pair generation is the process by which charge carriers are created in a semiconductor, leading to conductivity. This can happen through va...