Schottky Diodes and Detectors and Tunnel Diodes — Lesson 3

This lesson covers the functioning and applications of different types of diodes, including PN diodes, Schottky diodes, and tunnel diodes. It explains how PN diodes are used at low frequencies due to their large junction capacitance, while Schottky diodes, with their semiconductor-metal junction, are suitable for microwaves frequencies. The lesson also delves into the mathematical modeling of these devices, explaining the current flow, ideality factor, and saturation current. It further discusses the use of Schottky diodes for signal detection and the operation of tunnel diodes, which are highly doped PN junctions that allow electron tunneling, leading to negative resistance at high frequencies. The lesson concludes with a brief introduction to gun diodes.

Video Highlights

00:28 - Introduction to Schottky diodes and detectors
04:02 - Discussion on the use of Schottky diodes for signal detection
10:02 - Explanation of the process of demodulation operation in Schottky diodes
15:30 - Introduction to tunnel diodes and their features
20:25 - Tunnel diode operation
33:56 - Discussion on the negative resistance region of operation in tunnel diodes
36:38 - Amplification process with a tunnel diode
38:44 - Conditions under which a tunnel diode goes into oscillation

Key Takeaways

- PN diodes are used at low frequencies due to their large junction capacitance.
- Schottky diodes have a semiconductor-metal junction, resulting in a much lower junction capacitance, making them suitable for microwaves frequencies.
- Tunnel diodes, which are highly doped PN junctions, allow electron tunneling through a narrow energy bandgap, leading to negative resistance at high frequencies.
- Schottky diodes are used for signal detection due to their fast response.
- Tunnel diodes can be used for oscillators as well as amplifiers.