Which of the following is not a semiconductor?

The correct answer is arsenic (option D). Germanium, silicon, and selenium are all well-known semiconductors, crucial in the development of electronic devices such as diodes, transistors, and integrated circuits. These materials have properties that allow them to conduct electricity under certain conditions, making them essential for controlling electrical currents in various applications. Arsenic, on the other hand, is not a semiconductor. It is commonly used as a dopant in semiconductor manufacturing to modify the electrical properties of materials like silicon and germanium, improving their conductivity by introducing impurities. While arsenic plays a vital role in the semiconductor industry, it itself does not exhibit semiconductor properties. Understanding the distinction between semiconductors and dopants is crucial for comprehending how electronic components function and are manufactured.