Question

The intrinsic semiconductor behaves as insulator at?

• A. $0\mathrm{K}$
• B. $0°\mathrm{C}$
• C. $100\mathrm{K}$
• D. $100°\mathrm{C}$

Answer 1

The correct option is A

$0\mathrm{K}$

Explanation for the correct option:

Option (A):$0\mathrm{K}$

1. The intrinsic semiconductor is a type of semiconductor, which does not have any impurities present in it, hence the conducting electrons of an intrinsic semiconductor leave the valence shell leaving behind a hole.
2. The gap between the conduction band and the valence band, that is, the forbidden gap for an intrinsic semiconductor, will be approximately equal to the value of $1\mathrm{eV}.$
3. At the temperature, $\mathrm{T}=0\mathrm{K}$, which is the absolute temperature, the electrons of the valence band will remain in this band only, as they don’t get enough energy to jump to the upper forbidden band.
4. As the electrons cannot jump to the conduction band at this temperature, thus, the electricity will not be conducted and the semiconductor becomes an insulator in nature.

Explanation for the incorrect option:

Option (B):$0°\mathrm{C}$

1. At the temperature of $0°\mathrm{C}\mathrm{or}273\mathrm{K}$,the electrons of the valence band get sufficient energy to jump to the upper forbidden band.
2. Hence, at this given temperature the intrinsic semiconductor can not behave as an insulator.

Option (C):$100\mathrm{K}$

1. At the temperature, $100\mathrm{K}$the electrons of the valence band can jump to the conduction band and can conduct electricity.
2. Thus, at this given temperature the intrinsic semiconductor can not behave as an insulator.

Option (D):$100°\mathrm{C}$

1. The intrinsic semiconductor gets sufficient energy to jump to the upper forbidden band and can conduct electricity at the given temperature of $100°\mathrm{C}\mathrm{or}373\mathrm{K}$.
2. At this the semiconductor behaves like an insulator, thus the given option is the incorrect one.

$\therefore$ Thus, the intrinsic semiconductor behaves as an insulator at $T=0K$.

Hence, option (A) is the correct answer.