A photo diode sensor is one type of light detector, used to convert the light into current or voltage based on the mode of operation of the device. It comprises optical filters, built-in lenses, and also surface areas. These diodes have a slow response time when the surface area of the photodiode increases.

A photodiode is a semiconductor device with a P-N junction that converts photons (or light) into electrical current. The P layer has an abundance of holes (positive), and the N layer has an abundance of electrons (negative). These moving charge carriers form the current (photocurrent) in the photodiode.