A semiconductor is a material which has electrical conductivity to a degree between that of a metal (such as copper) and that of an insulator (such as glass). Semiconductors are the foundation of modern electronics, including transistors, solar cells, light -emitting diodes (LEDs), quantum dots and digital and analog integrated circuits.
Diode – Di + ode
Di means two and ode means electrode. So physical contact of two electrodes is known as diode and its important function is alternative current to direct current.