Chapter 9, Problem 67E

Interpretation Introduction

Interpretation:

       The wavelength of the light emitted by Aluminium phosphide diode has to be calculated.

Concept introduction:

         According to Band theory of solids, the energy levels of a substance are imagined as “bands”.  There are two types of bands – valence band and conduction band. Low lying bands are valence band and conduction band where the conduction takes place, lies above the valence band. The energy gap between the valence band and conduction band is called “band gap”. The energy gap can be represented by Planck’s equation,

             $\begin{array}{l}\text{E}\text{=}\text{hν}\\ \text{where ν}\text{=}\frac{\text{c}}{\text{λ}}\\ \text{E}\text{=}\text{energy}\\ \text{h}\text{=}\text{Planck's constant}\\ \text{ν}\text{=}\text{frequency}\\ \text{c}\text{=}\text{velocity}\text{of}\text{light}\\ \text{λ}\text{=}\text{wavelength}\end{array}$