Photodiodes and Avalanche Photodetectors

This lecture covers the operation of p-i-n photodiodes, discussing the insertion of an undoped semiconductor layer to create a high-resistance region for absorption, the response time components including drift and diffusion, and the RC limited response time. It also explores the characteristics of commercial p-i-n photodiodes and the advantages of avalanche photodetectors with internal gain. The impact ionization process in avalanche photodetectors is explained, along with the factors influencing the generation rate. The lecture concludes with the structure of avalanche photodetectors, highlighting the absorption and gain mechanisms in the p-i-n structure.