In case of a practical p-n junction diode, the rise in the junction te...
The rise in temperature excites the charges, which go & recombine with the charges in the depletion region decreasing its width. Higher the temperature, lesser is the E.M.F required to turn on the device.
View all questions of this test
In case of a practical p-n junction diode, the rise in the junction te...
Junction Temperature and Depletion Region Width in a PN Junction Diode
In a practical p-n junction diode, the junction temperature plays a significant role in determining the characteristics and behavior of the diode. The rise in junction temperature affects the width of the depletion region in the diode.
Depletion Region in a PN Junction Diode
The depletion region is the region around the p-n junction where there are no free charge carriers (electrons or holes) present. It is formed due to the diffusion of charge carriers from the high concentration side to the low concentration side of the junction.
Effect of Junction Temperature on Depletion Region Width
When the temperature of the p-n junction diode rises, it affects the width of the depletion region. The increase in temperature causes the following changes:
1. Thermal Generation of Charge Carriers: As the temperature increases, the thermal energy of the atoms in the diode also increases. This leads to the generation of additional charge carriers (electrons and holes) due to thermal excitation. These additional charge carriers are generated in the depletion region, causing an increase in the width of the depletion region.
2. Diffusion of Charge Carriers: The increase in temperature also affects the diffusion of charge carriers across the p-n junction. Diffusion is the process by which charge carriers move from a region of higher concentration to a region of lower concentration. With the rise in temperature, the mobility of the charge carriers increases, leading to enhanced diffusion. This enhanced diffusion of charge carriers also contributes to the widening of the depletion region.
Conclusion
In conclusion, in a practical p-n junction diode, the rise in the junction temperature increases the width of the depletion region. This is due to the thermal generation of charge carriers and the enhanced diffusion of charge carriers caused by the increase in temperature. Therefore, option 'A' is the correct answer.