What is meant by avalanche photodiode?
An avalanche photodiode (APD) is a highly sensitive semiconductor photodiode detector that exploits the photoelectric effect to convert light into electricity.
How does avalanche photodiode work?
Avalanche photodiode working principle. Avalanche breakdown takes place when the diode is subjected to high reverse voltage. The reverse bias voltage increases the electric field across the depletion layer. Incident light enters the p+ region and further gets absorbed in the highly resistive p region.
What is the difference between a PIN diode detector and an avalanche photo detector?
They are high-sensitivity, high-speed semiconductor light sensors. The main advantage of the APD is that it has a greater level of sensitivity compared to PIN. The avalanche action increases the gain of the diode many times, providing much higher sensitivity. However, an APD requires a higher operating voltage.
What is impact ionization in avalanche photodiodes?
Impact ionization is the process in a material by which one energetic charge carrier can lose energy by the creation of other charge carriers. In an avalanche photodiode the original charge carrier is created by the absorption of a photon. In some sense, impact ionization is the reverse process to Auger recombination.
Why are photodiodes operated in reverse bias condition?
When the diode is reverse biased, no ordinary current flows and the detection of the photo-current is much easier. B) When the diode is reverse biased, ordinary current flows and the detection of the photo-current is much easier.
What are the drawbacks of avalanche photodiode?
Avalanche photodiode disadvantages: Much higher operating voltage may be required. Avalanche photodiode produces a much higher level of noise than a PN photodiode. Avalanche process means that the output is not linear.
What is ionization of semiconductor?
process in which an atom is converted into an ion by giving away one or more of its electrons. energy needed to ionize dopant atom in semiconductor, i.e. to have dopant atom to release one free electron (donor) or one free hole (acceptor).
What causes avalanche breakdown?
Avalanche breakdown usually occurs when a high reverse voltage is applied across the diode. So as we increase the applied reverse voltage, the electric field across the junction will keep increasing. This generated electric field exerts a force on the electrons at the junction and it frees them from covalent bonds.
Under what conditions does avalanche breakdown occur?
The avalanche breakdown occurs when a high reverse voltage is applied across the diode. As we increase the applied reverse voltage, the electric field across the junction increases. This electric field exerts a force on the electrons at the junction and frees them from covalent bonds.
What is the maximum sensitivity of an avalanche photodiode?
With 650 nm to 850 nm for high cut-off frequencies, this avalanche photodiode is a perfect match for many devices and industrial applications such as laser scanning or optical communication. Their enhanced near-infrared (NIR) sensitivity of up to 900 nm makes these avalanche diodes the ideal choice for LIDAR / LADAR applications.
What is an avalanche breakdown detector?
This process is called avalanche breakdown and can thus achieve an avalanche multiplication factor of several hundred for the detector. Avalanche photodiodes are faster and more sensitive than conventional photodiodes. Additionally, the spectral response of avalanche photodiodes is particularly high.
Why shouldn’t avalanche diodes be used in mobile applications?
When avalanche diodes are operated outside of room temperatures in mobile applications, this can quickly lead to changes in the operating voltage and/or breakdown voltage, gain, dark current, sensitivity, capacitance, rise time, and total current.
How do APD photodiodes work?
Information about APD photodiodes. Avalanche photodiodes are diodes with an internal gain mechanism. As in the case of standard diodes, photons generate electron-hole pairs, which are accelerated by the applied external voltage such that further electrons are introduced to the conduction band by means of impact ionization.