Book 27, Question 109
Why does the gap in an LED chip decide its color?
An LED is a tiny crystal chip.
When electricity flows, electrons drop across a tiny gap in the crystal’s energy, and they give off the extra energy as light. A bigger gap makes bluer light, and a smaller gap makes redder light. Makers choose crystals with the gap for the color they want. Blue LEDs were so hard to make that three scientists won a Nobel Prize in 2014.