Question

How can we turn germanium or silicon into a semiconductor?

Answer 1

Step 1: Semiconductor

1. Most modern electronic devices are made of semiconductors.
2. Insulators practically do not conduct current, while metals are good conductors of electricity.
3. Semiconductors are materials whose conductivity lies in between those of an insulator and a conductor.
4. All semiconductors behave like a perfect insulator at absolute zero.
5. Contrary to the metals semiconductors have a negative temperature coefficient of resistance, i.e, they show a reduction in resistance with an increase in temperature.

Step 2: Doping

1. In semiconductors, the current is carried by two types of carries whereas in metals current is carried only by free electrons.
2. Silicon (Si) and Germanium (Ge) are the two most commonly used electronic device materials.
3. Si and Ge are turned into a semiconductor through the process of doping where impurities are added to these metals.
4. Depending on the doped impurity, whether they are doped with donor atoms or acceptor atoms n or p-type semiconductors are produced.
5. However, as a semiconductor device material Si is superior to Ge.
6. Nowadays electronic devices are being made almost entirely of Si.
7. Apart from Ge and Si, there are compounds like gallium arsenide (GaAs), indium phosphide (InP), indium arsenide (InAs), etc. which show semiconducting properties. These are called compound semiconductors.

Hence, germanium or silicon can be turned into a semiconductor by doping.