Answer: Discrete energy levels and size-tunable bandgap.
- A A continuous, bulk-like band structure with little discrete levels
- B Discrete energy levels and size-tunable bandgap
- C Metallic, conductor-like behavior with little bandgap
- D A bandgap that shrinks to exactly zero regardless of dot size
Correct answer: B. Discrete energy levels and size-tunable bandgap
Explanation: Quantum confinement: when size < de Broglie wavelength, energy levels become discrete. Bandgap increases as size decreases. Used in tunable LEDs.
Conductors have overlapping bands, semiconductors have a small energy gap that can be bridged by heat or doping, and insulators have a large gap that blocks conduction.
Concept context
Band theory, p-n junction, diodes, transistors, logic gates, and integrated circuits.