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## QuestionPhysicsClass 12

$$C,\mathit{Si}$$ and $$Ge$$have same lattice structure. Why is $$C$$ insulator while $$\mathit{Si}$$ and $$Ge$$ intrinsic semiconductors?

See explaination below
4.6
4.6

## Solution

The four bonding electrons of C, Si or Ge are lie respectively in the second, third and forth orbit. The energy gap for Ge is $$0\mathrm{\ldotp }72eV$$, for Si is $$1\mathrm{\ldotp }1\,eV$$and for C is $$5\mathrm{\ldotp }54\,eV$$. Hence, energy required to take out an electron from these atoms will be least for Ge and highest for C. Therefore, the C is insulator and and Si and Ge are intrinsic semiconductor.