Semiconductor diodes — match each diode type (List I) with the most accurate statement (List II). List I (Diode) A. Tunnel diode B. PIN diode C. Zener diode D. Schottky diode List II (Statement) 1. Also known as a hot-carrier (metal–semiconductor) diode 2. Used primarily with reverse bias (regulated breakdown) 3. Has an intrinsic (undoped) layer between P and N 4. v–i characteristic exhibits an “N” shape with a negative-resistance region

Introduction / Context:
Different diode structures produce distinct electrical behavior. Recognizing the signature property of each device is essential for RF design, switching supplies, detectors, and protective circuits.

Given Data / Assumptions:

• Tunnel diodes are heavily doped and support quantum tunneling with a negative-resistance region.
• PIN diodes insert a wide intrinsic region, useful for RF switching/attenuation and photodiodes.
• Zener diodes operate in breakdown under reverse bias for voltage regulation.
• Schottky diodes form a metal–semiconductor junction (hot-carrier), yielding low forward drop and fast recovery.

Concept / Approach:

Match each physical structure to its hallmark behavior: negative resistance (Tunnel), intrinsic region (PIN), reverse-biased breakdown use (Zener), and metal-semiconductor junction (Schottky).

Step-by-Step Solution:

Verification / Alternative check:

Datasheets and characteristic curves confirm these properties: e.g., Schottky forward drop ≈ 0.2–0.3 V; tunnel diode shows a peak and valley current; Zeners specify breakdown voltage; PIN diodes specify I-region width and RF parameters.

Why Other Options Are Wrong:

• Interchanging Schottky with Zener or PIN ignores junction physics.
• Assigning “reverse-bias use” to the tunnel diode confuses its use as a microwave oscillator/amp exploiting negative resistance.

Common Pitfalls:

Assuming all diodes are P–N; Schottky lacks a P–N junction. Not all breakdown diodes are “Zeners”; avalanche breakdown is also common at higher voltages.

Final Answer:

A-4, B-3, C-2, D-1