Semiconductor device are electronic components that exploit the electronic properties of Semiconductor materials , principally silicon, germanium and gallium arsenide , as well as organic semiconductors . Semiconductor devices have replaced thermionic devices (vacuum tubes) I'm most applications . They use electronic conduction in the solid state as opened to the gaseous state or thermionic emission in the high vacuum.

TYPES OF SEMICONDUCTORS

1) Intrinsic semiconductor

2) Extrinsic semiconductor