Introduction

With the help of computer programs, you have been able to use the energy level diagram to explain the spectra emitted by gas lamps. You will now apply what we have learned to explain the spectra emitted by LEDs.

The study of gas spectra has led you to the conclusion that only certain energy levels can exist in a gas atom. Now, we wish to extend our investigation to solids so that we understand how LEDs emit light. As a first step we will explore how we might create a spectrum similar to that of an LED.