This question paper evaluates the understanding of semiconductor physics, pn junction behavior, BJT and MOSFET operation, quantum mechanics fundamentals, and carrier transport mechanisms. It is divided into three structured sections:
SECTION A — Short Answer Questions (20 Marks)
This section contains 10 conceptual questions, each carrying 2 marks, designed to test fundamental knowledge of:
Energy band theory and classification of materials Carrier transport (drift vs diffusion)
PN junction diode characteristics and depletion region BJT current gain, CE configuration
MOSFET small-signal modeling Photovoltaic effect and basic semiconductor physics
These questions require brief, clear, and to-the-point responses.
SECTION B — Descriptive / Analytical Questions (30 Marks)
Attempt any three out of five (10 marks each).
This section tests deeper understanding of:
Effective mass and band structure curvature
Semiconductor doping calculations, Fermi level, and band diagrams
Continuity equation derivation using drift and diffusion concepts
Zener vs Avalanche breakdown
Applications of optoelectronic devices (LED, Solar cell)
Answers must include equations, diagrams, and proper explanations.
SECTION C — Long Answer / Application-Based Questions (50 Marks)
Attempt one question from each of the five groups.
These questions check advanced proficiency, problem-solving, and derivations:
Quantum Mechanics: Time-dependent & time-independent Schrödinger equation
Band Theory: Direct vs indirect band gaps, alloy variation
Carrier Statistics: Fermi-Dirac function, Einstein relation
PN Junction: Depletion width derivation, numerical problems on doped junctions
Devices:
Schottky diode BJT Ebers-Moll model
MOS capacitor (accumulation, depletion, inversion) MOSFET characteristics
Each question carries 10 marks, and students must show detailed derivations, reasoning, diagrams, and relevant formulas.
Purpose of the Question Paper
The paper assesses a student's ability to:
Understand semiconductor physics deeply
Analyze device behavior under different conditions
Apply mathematical modeling to electronic devices
Draw and interpret energy band diagrams
Solve numerical problems related to doping, depletion regions, and capacitances
Explain device operations such as BJT, MOSFET, PN junctions, and optoelectronic devices
