Types of Semiconductors
When voltage is applied to semiconductor devices, the current of electrons flows to the positive side of the Current from the source and the holes flows to the negative side of the source. Such a situation occurs only in a semiconductor material.
Silicon and germanium are the most common semiconductor materials. Typically, the conductivity of a semiconductor lies between the conductivities of ls and insulators.
Germanium as a semiconductor
Here are some important points about Germanium -
There are four electrons in the outermost orbit of germanium. In bonds, atoms are represented with their outer electrons only.
Germanium atoms will share valence electrons in a covalent bond. This is illustrated in the following figure.Germanium is the one associated with the covalent bond. The crystal form of germanium is called crystal lattices. This type of structure has the atoms arranged as shown in the following figure.
In such an arrangement, electrons are in a very stable state and are therefore less suitable to associate with conductors. In its pure form, germanium is an insulating material and is called an intrinsic semiconductor .
The following figure shows the atomic structures of silicon and germanium.
Silicon as a semiconductor
Semiconductor devices also use silicon in the manufacture of
Here are some of the important points about silicon -
It has four electrons in its couche outermost like germanium.
In its pure form, it is useless as a semiconductor device.
A desired amount of conductivity can be achieved by adding impurities.
Addition of impurities should be done with care and in a controlled environment.
Depending on the type of impurity added, this will either create an excess or a deficit of electrons.
The following figure shows the intrinsic crystal of silicon.