Answer: Non-radiative recombination, optical extraction losses, and interface defects.
- A The doping concentration alone, with all other factors fixed in many documented cases
- B Non-radiative recombination, optical extraction losses, and interface defects
- C The applied forward voltage alone, independent of material quality according to conventional understanding
- D The temperature coefficient of resistivity of the semiconductor in routine practice
Correct answer: B. Non-radiative recombination, optical extraction losses, and interface defects
Explanation: LED efficiency: quantum efficiency limited by non-radiative recombination (Auger, defect), light extraction (total internal reflection), series resistance.
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.