Photoconductivity: Light Switching Electricity

Light isn't just for seeing, it is actually a physical switch that controls electricity.

This is the magic of photoconductivity. Basically, semiconductors are super lazy in the

dark. They have high resistance and barely let any current through, known as dark current.

But the second you hit them with light, it’s chaos. Photons smash into electrons,

giving them enough energy to jump the energy band gap. This creates electron-hole pairs and suddenly

the material becomes conductive. The brighter the light, the more current

flows until it hits saturation. It is the exact science behind how automatic streetlights

and camera sensors work.