Official Correct Choice:
Option C: Silicon has a higher melting temperature, lower reverse saturation current, and higher breakdown voltage
Concept:Silicon has a wider energy bandgap (\( 1.1\text{ eV} \) vs \( 0.67\text{ eV} \)), giving it superior thermal stability, higher breakdown ratings, and lower leakage current than germanium.
Formula:$$I_0(\text{Si}) \approx 10^{-9}\text{ A (nA)}, \quad I_0(\text{Ge}) \approx 10^{-6}\text{ A (}\mu\text{A)}$$
Solution:- The wider bandgap of silicon results in much lower reverse saturation current (nA for Si vs \( \mu\text{A} \) for Ge).
- Silicon can operate at higher junction temperatures (up to \( 150^\circ\text{C}-200^\circ\text{C} \)) compared to germanium (limited to \( \approx 75^\circ\text{C}-100^\circ\text{C} \)).
- Silicon devices also offer higher Peak Inverse Voltage (\( \text{PIV} \)) ratings, making them better suited for power rectification.
Why other options are incorrect:- Option A: Silicon has a higher barrier potential (\( 0.7\text{ V} \)) than germanium (\( 0.3\text{ V} \)).
- Option B: Silicon has a much lower reverse leakage current than germanium, which is an advantage.
- Option D: Silicon operates as a standard semiconductor; it does not exhibit superconductivity at operating temperatures.
Quality & Fidelity Assurance:
Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.