APPLICATION

1. RF switching: The RF resistance of a p-i-n diode is controlled by the quiescent bias. This feature makes it practical as a circuit, called a series switch. When the diode is forward biased it is considered a short. At zero or reverse bias, it is considered a capacitor or an open circuit.

2. Attenuation and modulation: Because the RF resistance is a continuous function of quiescent bias, it can be varied to attenuate and modulate the RF signal. The modulation frequency is limited by the reverse recovery. RF switching is an extreme case of attenuation and modulation.

3. Phase shifting: Phase shifting of an RF signal can be achieved by using transmission lines of different lengths. The p-i-n diodes can be used as switches for selecting these transmission lines.

4. Limiter: As mentioned before, at RF frequencies, a p-i-n diode behaves like a pure resistor. However, this is valid only when the RF signal is below a critical level. Above this level, the RF resistance drops, similar to that of the DC resistance. This property enables it to be used for protection of radar receivers, when it is connected in parallel, against excessive transmitter power.

5. Power rectifier: Due to the thick intrinsic layer, a p-i-n diode has a high breakdown voltage and can be used as high power rectifier.

6. Photodetector: For a photodetector, a wide region with a built-in field is advantageous such that light can be completely absorbed within this region. A p-i-n structure is used as a nuclear-radiation detector and is one of the most common photodetectors.