Question

How many elements in group 14 are used as semiconductors?

Answer 1

Hint: These elements have 4 electrons in their valence shell and with an increase in temperature, they create both free electrons and holes for conduction of electricity. Due to this property, they are widely used in electronics. In the periodic table, they are classified either as metals or as non-metals.

Complete step by step solution:
-First of all, let us see what semiconductors are.
Basically, semiconductors are those materials which have a conductivity between conductors (metals) and insulators (like ceramics). For example germanium (Ge), silicon (Si), Gallium arsenide, etc.
In semiconductors, the current flow occurs through holes and electrons; which means that they act as charge carriers. The holes are the positively charged charge carriers and the electrons are the negatively charged particles. But the mobility of electrons is much more than that of the holes.
-According to the band theory, the valence band in semiconductors is much smaller than insulators and so an application of external energy can easily cause the electrons to jump across the valence band to the conduction band.
-Semiconductors can conduct electricity but under specific conditions only and in them the charge carriers arise due to external thermal agitation. Let us just take a look at some specific properties of the semiconductors:
 1) Resistivity: ${10^{ - 5}}$ to ${10^6}\Omega m$
 2) Conductivity: ${10^5}$ to ${10^{ - 6}}$ mho/m
 3) Temperature coefficient of resistance: (-ve) Negative
 4) Current flow: via electrons and holes
-Now coming back to the question we need to tell the semiconductors in group 14 of the periodic table.
The group 14 of the periodic table is the carbon group and the elements present in it are Carbon (C), Silicon (Si), Germanium (Ge), Tin (Sn) and Lead (Pb). Out of these Si and Ge behave as semiconductors.
-Silicon and germanium act as intrinsic semiconductors since they have 4 valence electrons (they are tetravalent) and so are bound to atoms via covalent bonds at absolute zero temperatures. Due to an increase in temperature, the number of collisions increase which cause some electrons to become free to move around the lattice further creating holes in their original position. This is how the electrons and holes act as charge carriers in the semiconductors.
So, the semiconductor elements present in group 14 are Silicon (Si) and Germanium (Ge).

Note: The semiconductors have various applications like temperature sensors, 3D printing machines, in microchips, transistors, LEDs, solar cells, etc. They are extremely useful because they require less power input, are highly portable because of small size, are shockproof, have a longer lifespan and also do not cause noise while operating.