Infrared photosensitive diode, also known as an infrared photodiode, is a semiconductor device that converts infrared radiation into an electrical signal. As the core component of infrared detection systems, it plays a crucial role in various fields such as security, communication, medical equipment, and industrial automation. This article will introduce the development, working principle, application, and future prospects of infrared photosensitive diodes.

Development of Infrared Photosensitive Diodes

The development of infrared photosensitive diodes can be traced back to the early 20th century. In 1908, a German physicist named Hans Geiger discovered that certain materials could produce an electric current when exposed to infrared radiation. In 1916, the British physicist William Henry Bragg proposed the concept of a photodiode, which can convert light into an electric signal. With the continuous development of semiconductor technology, infrared photosensitive diodes have become an indispensable component in various applications. In the 1950s, the first generation of infrared photosensitive diodes was developed. At that time, the main material was selenium, which had a relatively low sensitivity and was easily damaged by heat. In the 1960s, the development of silicon materials brought about a significant breakthrough in the field of infrared photosensitive diodes. With the improvement of material quality and manufacturing technology, the sensitivity and stability of infrared photosensitive diodes have been greatly improved. In the 1970s, the development of infrared photosensitive diodes entered a new stage. The introduction of compound semiconductor materials, such as gallium arsenide and indium gallium arsenide, greatly expanded the application range of infrared photosensitive diodes. At the same time, the research and development of infrared photosensitive diodes have been increasingly focused on the improvement of their performance and cost-effectiveness.

Working Principle of Infrared Photosensitive Diodes

The working principle of infrared photosensitive diodes is based on the photoelectric effect. When infrared radiation is incident on the semiconductor material, the energy of the photons is absorbed by the electrons in the material, causing the electrons to break away from the valence band and enter the conduction band. As a result, a photoelectric current is generated in the semiconductor material. The infrared photosensitive diode consists of a P-type semiconductor and an N-type semiconductor. When the two types of semiconductor materials are combined, a PN junction is formed. When infrared radiation is incident on the PN junction, the photoelectric current is generated, and the electrical signal is output. The output current of the infrared photosensitive diode is proportional to the intensity of the incident infrared radiation. Therefore, by detecting the output current, the intensity of the infrared radiation can be measured. The working principle of the infrared photosensitive diode is shown in Figure 1.  Figure 1: Infrared photosensitive diode working principle

Application of Infrared Photosensitive Diodes

Infrared photosensitive diodes have a wide range of applications due to their excellent performance and low cost. The following are some typical applications: 1. Security and surveillance: Infrared photosensitive diodes are used in security cameras, motion sensors, and other security equipment to detect human or animal movements and ensure safety. 2. Communication: Infrared photosensitive diodes are used in wireless communication systems, such as infrared remote controls, infrared data transmission, and infrared communication modules. 3. Medical equipment: Infrared photosensitive diodes are used in medical imaging equipment, such as infrared thermometers, to detect the temperature of the human body or other objects. 4. Industrial automation: Infrared photosensitive diodes are used in industrial automation equipment, such as conveyor belt sensors, to detect the presence or absence of objects on the conveyor belt. 5. Consumer electronics: Infrared photosensitive diodes are used in consumer electronics, such as infrared remote controls, to transmit signals to control the operation of electronic devices.

Future Prospects of Infrared Photosensitive Diodes

With the continuous development of technology, the performance and application range of infrared photosensitive diodes will continue to expand. The following are some future prospects: 1. High-sensitivity and high-speed detection: The development of new materials and manufacturing technology will enable infrared photosensitive diodes to achieve higher sensitivity and faster detection speed, which will further expand their application range. 2. Miniaturization and integration: The miniaturization and integration of infrared photosensitive diodes will make it possible to integrate them into various electronic devices, which will promote the development of smart devices. 3. Intelligent control: With the development of artificial intelligence, infrared photosensitive diodes will be combined with machine vision, pattern recognition, and other technologies to realize intelligent control and application. 4. New application fields: As the demand for infrared detection technology continues to grow, new application fields such as environmental monitoring, aerospace, and space exploration will emerge, providing a broad market space for infrared photosensitive diodes. In conclusion, infrared photosensitive diodes have become an indispensable component in various fields due to their excellent performance and low cost. With the continuous development of technology, the application range and market prospects of infrared photosensitive diodes will continue to expand, bringing more convenience and benefits to people's lives.