Question

Germanium is an example of?

• A. Insulator
• B. n-type semiconductor
• C. p-type semiconductor
• D. Intrinsic semiconductor

Answer 1

The correct option is D

Intrinsic semiconductor

The explanation for the correct option:

(D) Intrinsic Semiconductor

1. Semiconductors are substances with conductivities intermediate between conductors (often metals) and non-conductors or insulators. They are classified into two types intrinsic semiconductors and extrinsic semiconductors.
2. An intrinsic semiconductor, also known as an undoped semiconductor or an i-type semiconductor, is a pure semiconductor that doesn't have any significant amounts of dopant species present.
3. A semiconductor is referred to as an extrinsic semiconductor when it has been doped with impurities. Now, it also depends on the kind of doped impurity. It is of two types N-type semiconductor, and p-type semiconductor.
4. N-type semiconductors are those in which the impurity is composed of pentavalent elements whereas in p-type semiconductors impurity is composed of trivalent elements.
5. Germanium with atomic number$=32$ has an electronic configuration$1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}3{\mathrm{d}}^{10}4{\mathrm{s}}^{2}4{\mathrm{p}}^2$ that contains four electrons in its outermost orbit and is neither trivalent nor pentavalent. There are no impurities doped into the germanium element. As a result, it is an intrinsic semiconductor.
6. Hence, it is the correct option.

The explanation for Incorrect answer:

(A) Insulator:

1. Insulators are those that even after providing some heat or with some disturbance in the electronic structure doesn't able to pass the electron or conduct electricity.
2. But Germanium is not an insulator it is a semiconductor as it possesses properties between conductor and insulator.
3. Hence, it is an incorrect option

(B): n-type semiconductor

1. When a certain semiconductor is doped with impurities, then the semiconductor is known as an extrinsic semiconductor.
2. In the case of n-type semiconductors, the impurity consists of pentavalent elements.
3. But the germanium is not doped with any type of impurity.
4. Hence, it is an incorrect option.

(C): p-type semiconductor

1. If the impurity consists of trivalent elements, then the semiconductor is known as a p-type semiconductor.
2. But germanium has four valence electrons in its outer configuration. So it is neither an n-type semiconductor nor a p-type semiconductor, it is an intrinsic semiconductor i.e. a semiconductor without any impurities.
3. Hence, it is an incorrect option.

So, Germanium is an example of an intrinsic semiconductor.