Department of Pre-University Education, KarnatakaPUC Karnataka Science Class 12

# Suppose the Energy Liberated in the Recombination of a Hole-electron Pair is Converted into Electromagnetic Radiation. If the Maximum Wavelength Emitted is 820 Nm, What is the Band Gap? - Physics

Short Note

Suppose the energy liberated in the recombination of a hole-electron pair is converted into electromagnetic radiation. If the maximum wavelength emitted is 820 nm, what is the band gap?

(Use Planck constant h = 4.14 × 10-15 eV-s, Boltzmann constant k = 8·62 × 10-5 eV/K.)

#### Solution

Given:
Wavelength, lambda = 820  "nm"

The minimum energy released in the recombination of a conduction band electron with a valence band hole is equal to the band gap of the material.
Band gap, $E = \frac{hc}{\lambda}$

$\Rightarrow E = \frac{1240}{820}\frac{eV - \text{ nm}}{\text{ nm} }$

$\Rightarrow E = 1 . 5 \text{ eV }$

Concept: Energy Bands in Conductors, Semiconductors and Insulators
Is there an error in this question or solution?

#### APPEARS IN

HC Verma Class 11, Class 12 Concepts of Physics Vol. 2
Chapter 23 Semiconductors and Semiconductor Devices
Q 7 | Page 419