Semiconductors

Step 1: Understanding doping in semiconductors.
Doping is the process of adding small amounts of impurities to a semiconductor to change its electrical properties. The process introduces extra charge carriers (either electrons or holes) into the material, thus increasing its conductivity.
Step 2: Effect of doping.
- N-type doping adds extra electrons, increasing the number of negative charge carriers.
- P-type doping creates holes (positive charge carriers), which also increases conductivity.
Step 3: Conclusion.
Thus, doping increases the conductivity of a semiconductor, corresponding to option (A).