Which of the following is a Semiconductor?
Option 4 ( Germanium ) is the right answer.
chemical symbol – Ge
This type of semiconductor material was used in many early devices from radar detection diodes to the first transistors. Diodes show a higher reverse conductivity and temperature coefficient meant that early transistors could suffer from thermal runaway. Offers a better charge carrier mobility than silicon and is therefore used for some RF devices. Not as widely used these days as better semiconductor materials are available.