Question

What is Photodiode? Mention its one use.

Answer 1

Hint: To get detail information about Photodiodes and its uses first of all we have to understand the operation of p-n junction diode in reverse bias mode and how the concentration of doping during fabrication of p-n junction diode opens the windows for the application of p-n junction diode in the area of optoelectronics. (Optoelectronics is the study and application of electronic devices which are specially designed to detect and control the light.)

Complete step by step answer:
Definition:
A semiconductor (special type of p-n junction) device that converts light energy into electrical energy. It works on the principle of the inner photoelectric effect. The solar cell is one great example of a photodiode.

Explanation:
It is a p-n junction device. It consumes light energy and leads to a change in the conductivity. It is used in reverse bias condition. When a light incident on the p-n junction diode, it creates electron-hole pairs that increase the conductivity in the circuit. Photodiodes are very sensitive to the incident light. It is a voltage-driven device. It has high gain along with low noise. Also, they have low sensitivity towards the temperature fluctuations, so they have a high working temperature range.

Use:
The photodiode is widely used in the measurement of the intensity of light in various research industries due to its enhanced responsiveness than photoconductors.

Note:
In order to tackle these kinds of theoretical questions, students should have to understand the concept behind the working principle of the photodiode and analyze the (I-V) characteristic curve for photodiode to grasp the In-depth theoretical concepts. One should also learn how the output current varies with changing the frequency, wavelength, and intensity of incoming radiation.