Concept:Zener breakdown occurs via quantum tunneling across a narrow junction, while Avalanche breakdown occurs via impact ionization from accelerated carriers.
Formula:$$\frac{dV_Z}{dT} < 0 \quad (\text{Zener, } V_Z < 4\text{ V}), \quad \frac{dV_{\text{av}}}{dT} > 0 \quad (\text{Avalanche, } V_{\text{av}} > 6\text{ V})$$
Solution:- In Zener breakdown, higher temperature narrows the bandgap, facilitating tunneling and lowering the required breakdown voltage (negative temperature coefficient).
- In Avalanche breakdown, higher temperature increases lattice vibrations, causing carriers to scatter more frequently and requiring a higher reverse voltage to gain ionizing energy (positive temperature coefficient).
Why other options are incorrect:- Options A, C, & D: These do not reflect the opposing temperature coefficients of the two breakdown mechanisms.
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