Working of Photodetector
The basic principle of the photodetector is that when an incident light or radiation falls on the surface of detector and get absorbed, it converts it into electrical signals.
Photodetector acts as a reversed biased p-n junction. Let’s understand how the photodetector works-
There are three process works in the operation of the photodetector:
- Absorption
- Transportation of Carriers
- Extraction of Carriers As Photocurrent
Absorption
In this process, the light energy falls on the photodetector which gets absorbed by it. As we know light carries small packets of energy known as photons which means several photons are absorbed by the photodetector. Due to this,
• There is the generation of charged carriers in the device.
• These carriers are the electron-hole pairs (e- and h+).
Transportation of Carriers
In this process, the generated charge carriers get transported across all the absorption regions. In some photodetectors, a gain is provided to the charged carriers which means there is multiplication of photons which increases during the transportation.
Extraction of Carriers As Photocurrent
After the successful transportation of charged particles (electron-hole pairs), the collection of these carriers is done and the current as an electrical signal flows through the external circuit.
The current is generated mainly because of the photons that fall on the photodetector, that is why it is also called a photocurrent.
Photodetector
A photo is nothing but light. A detector is nothing but a device that detects something. Therefore, we can directly conclude that a photodetector can be defined as a device that is used to detect light radiations by absorption. In this Article, We will be going through Photodetector, We will start our Article with What is Photodetector?, Then we will go through its brief Working, then we will go through its properties and go through all the types, At last, we will conclude our Article with Advantages, Disadvantages and Some FAQs.
Table of Content
- What is PhotoDetectors ?
- Working of PhotoDetector
- Classes of PhotoDetector
- Photodetector Properties
- Types of PhotoDetector
- Comparison Between Photodetector and Photodiode
- Applications of Photodetector