A semiconductor is a material that lies between conductors (such as copper) and insulators (such as glass) in terms of electrical conductivity. Here are some key points about semiconductors: Conductivity Range : Semiconductors have intermediate electrical conductivity. Their resistivity generally decreases as temperature rises, unlike metals. Examples include silicon, germanium, and gallium arsenide. Doping and Impurities : Semiconductors can be modified by introducing impurities (doping) into their crystal structure. Doping creates differently conducting regions within the same crystal, forming semiconductor junctions. These junctions are the basis for diodes, transistors, and modern electronics. Applications : Semiconductors are used for amplification, switching, and energy conversion. They exhibit properties like variable resistance, sensitivity to light, and heat responsiveness. Silicon, the most common semiconductor, is critical for electronic circuits. Quantum...