Lecture
This lecture discusses the principles and applications of induced photodiodes, particularly focusing on the induced PN junction with black silicon. The instructor explains the structure of the photodiode, which consists of a low-doped N-silicon substrate and P layers at the surface, coated with aluminum oxide. The lecture highlights the advantages of using black silicon, emphasizing its ability to achieve total light absorption across various wavelengths due to its nanostructured surface. The instructor details the working mechanism, describing how light absorption generates electron-hole pairs, with electrons moving to the substrate and holes collected in the P-channel. The concept of an induced PIN photodiode is introduced, along with comparisons to ion-sensitive field-effect transistors (ISVETs). The lecture also covers the impact of pH levels on the performance of ISVETs, illustrating how the threshold voltage varies with the presence of positive or negative ions. Overall, the lecture provides a comprehensive overview of the induced photodiode's functionality and its potential applications in optical detection.