Name: Photovoltaic Cell: Principle and Working
Uploaded: 2019-07-19
Duration: 5 min 15 s
Description: A photovoltaic cell (PV cell) is a specialised semiconductor diode that converts the visible light into direct current. Let's watch the video and learn.

Question

Distinguish between zener breakdown and avalanche breakdown.

Accepted Answer

The differences between zener breakdown and avalanche breakdown can be understood under the following heads:

(i) Mechanism: Zener breakdown occurs due to the high electric field. When the reverse voltage equals the zener voltage, then the field strength is high enough to pull the electrons from the host atoms on $p -$ side which are accelerated to $n -$ side. In the avalanche breakdown, the reverse voltage increases the speed of charge carriers, which collide with other atoms and generate more electron-hole pairs.

(ii) Width of depletion region: For Zener breakdown to occur, the width of the depletion region is less as compared to avalanche breakdown.

(iii) Electric field at the depletion region: It is much higher in the case of zener breakdown, because its mechanism is based on the pulling of electrons from the atoms. Force on electrons increases with the applied electric field.

(iv) Doping: Much higher doping is required for the Zener breakdown to occur as compared to avalanche breakdown.

(v) After breakdown: The junction can not be restored after a breakdown in Avalanche breakdown. Zener breakdown does not permanently destroy the junction. It can be restored at its position.

Distinguish between zener breakdown and avalanche breakdown.

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