This document discusses photodiodes, which are semiconductor devices that convert light into electrical current. It describes the history and development of photodiode technology since the 1940s using materials like silicon and germanium. The key features, types (PIN, PN, and avalanche), construction, characteristics, applications, and advantages/disadvantages of photodiodes are examined. Photodiodes are commonly used as photo detectors in applications like cameras, optical switches, and consumer electronics due to properties such as high sensitivity, low noise, and compact size.

1. Dept. of Computer Science & Engineering
Faculty of Engineering
University of Development Alternative (UODA)

2. Participants

3. Contents
 What is Photodiode
 History & Theory
 Features of photodiode
 Materials
 Types
 Photodiode Construction
VI characteristics of photo diode
Applications
Advantages & Disadvantages
Reference

4. What is Photodiode ?
A photodiode is a
semiconductor
device that
converts lights into
current.

5. Photodiode technology developed since 1940s
Photodiode technology was refined in the 1950s
Silicon has been the favoured material for
photodiodes, germanium can also be used, and its
use was first demonstrated in 1962 by Riesz.
History & Theory

6. Excellent linearity with respect to incident
light
Low noise
Wide spectral response
Mechanically rugged
Compact and lightweight
Long life
Features of photodiode

7. Materials commonly used to produce photodiodes
include:
Materials

8. Types:
PIN photodiode
PNphotodiode
Avalanche photodiode
Types

9. Photodiode Construction
CROSS SECTION OF THE SILICON PHOTODIODE

10. VI characteristics of photo diode

11.  Photo diodes are used as photo detectors.
 Photo diodes are used in cameras as photo sensors,
Slotted optical switch, in scintillators e.t.c.
 Photo diodes are used in consumer electronics.
Applications

12. Advantages:
 Photodiode detector are high NIR sensitivity and high
speed.
 Low noise
 Low dark current
Disadvantages:
 Normal PN junction photo diodes have very high
response times.
 It has very low sensitivity
Advantages & Disadvantages

14. Thank you all
&
Special thanks to our honorable teacher
Farzana Rahman Mishu
Sr. lecturer
Dept. of Computer Science & Engineering
Faculty of Engineering

16. Created by Mohammad Ali Khan
Dept. Computer Science & Engineering
Faculty of Engineering
University of Development Alternative (UODA)