Photo diode

Physics presentation on photo diode

1. Presentation of PHYSICS Photo diode

2. Group members Zain ul Abidien (Leader) 439 Asad Ali 481 Junaid Babar 407 Zain ul Abidien 406 Faizan Arif 443 Shamon 463

3. What is Photodiode ? A photodiode is a PN-junction diode that consumes light energy to produce an electric current. They are also called a photo-detector, a light detector, and a photo-sensor. Photodiodes are designed to work in reverse bias condition. Typical photodiode materials are Silicon, Germanium and Indium gallium arsenide.

4. Construction The photodiode is made up of two layers of P-type and N-type semiconductor . In this, the P-type material is formed from diffusion of the lightly doped P-type substrate. Thus, the layer of P+ ions is formed due to the diffusion process. And N-type epitaxial layer is grown on N-type substrate .

5. Working of Photodiode When the Photodiode is illuminated with light, with Energy greater than Energy gop of the Semi-Conductor than electron hole puir are generated due to the absorption of photons these charge Carriers. Contribute to the reverse current.

6. Uses of Photodiode In photodetection for optical signals. In demodulation for optical signals. In optical communication equipment. In counting machine.

7. V-I Characteristics I1,I2,I3 and I4 is not a current ,It is intensity of light. On increasing intensity , reverse current also increase.

8. Dark Current When the photodiode is reverse biased with a voltage less than its breakdown voltage and no light is incident on its junction the reverse current is extremely small . This current is called dark current .

9. Types of photodiode PIN photodiode. P-N photodiode. Avalanch photodiode.