Question 211: Semiconductors and Logic Gates

Question

The energy band gap of semiconducting material to produce violet (wavelength = 4000$$\mathop A\limits^o $$ ) LED is ______________ $$\mathrm{eV}$$. (Round off to the nearest integer).

Accepted Answer

Energy corresponding to wavelength 4000 $$\mathop A\limits^o $$
$$E = {{hc} \over \pi }$$
$$ = {{6.6 	imes {{10}^{ - 34}} 	imes 3 	imes {{10}^8}} \over {4000 	imes {{10}^{ - 10}} 	imes 1.6 	imes {{10}^{ - 19}}}}$$ eV
$$ = {{12400} \over {4000}}$$
$$=3.1$$ eV
$$\approx$$ 3 eV

Semiconductors and Logic Gates

The energy band gap of semiconducting material to produce violet (wavelength = 4000$\mathop A\limits^o ) LED is ______________ \mathrm{eV}$. (Round off to the nearest integer).

Choose the correct answer: