What is the responsivity of a photodetector?
Photodetector responsivity (defined by Equation 1.2. 2 in Chapter 1) is a measure of optical-to-electrical conversion efficiency of a photodetector and is usually expressed by the value of the photocurrent (mA) generated by each milliwatt of optical signal.
What is MSM photodetector?
A metal-semiconductor-metal (MSM) photodetector consists of interdigitated metal fingers on a semiconductor, and it detects photons by collecting electric signals generated by photoexcited electrons and holes in the semiconductor which drift under the electrical field applied between the fingers.
What is the function of the photodetector?
Photodetectors are sensors that can convert the photon energy of light into electrical signal. They are absolutely necessary for various scientific implementations like fiber optic communication systems, process control, environmental sensing, safety and security, and also in defense-related applications.
Which are characteristics of a photodetector?
Photodetectors are characterized by certain key parameters. Among them are spec- tral response, photosensitivity, quantum efficiency, dark current, forward-biased noise, noise equivalent power, terminal capacitance, timing response (rise time and fall time), frequency bandwidth, and cutofffrequency.
How do you get responsivity?
You need to know the spectral irradiance which is the incident irradiation power per wavelength interval at the different wavelength of the measurement range. Assuming this power is P(lambda) watt/ um , Then you obtain the responsivity by dividing the total current to the total power.
What is meant by responsivity?
Responsivity is defined as the output signal (typically voltage or current) of the detector produced in response to a given incident radiant power falling on the detector.
Is photodiode and photodetector same?
As nouns the difference between photodiode and photodetector is that photodiode is a semiconductor two-terminal component whose electrical characteristics are light-sensitive while photodetector is any device used to detect electromagnetic radiation.
What is a Photoreceiver?
Photoreceivers are based on the same types of semiconductor photodiodes used for power sensors (see Photodiode Sensor Physics) and camera-based beam profiling (see Laser Beam Profile Measurement). They also share many common parameters that must be considered when selecting a detector for any application.
What are the two main types of photodetectors?
Common Types of Photodetectors
- p-n Photodiodes.
- p-i-n Photodiodes.
- Avalanche Photodiodes.
- MSM Photodetectors.
What is required for good performance of photodetectors?
Depending on the application, a photodetector has to fulfill various requirements: It must be sensitive in a certain spectral region (range of optical wavelengths). In some cases, the responsivity should be constant or at least well defined within some wavelength range. It depends on the optical wavelength.
What is responsivity in optical communication?
Responsivity measures the input–output gain of a detector system. In the specific case of a photodetector, it measures the electrical output per optical input. A photodetector’s responsivity is usually expressed in units of amperes or volts per watt of incident radiant power.
How do photodiodes work?
Principle of operation A photodiode is a PIN structure or p–n junction. When a photon of sufficient energy strikes the diode, it creates an electron–hole pair. Thus holes move toward the anode, and electrons toward the cathode, and a photocurrent is produced.
How does asymmetric ratio affect the responsivity of self-powered UV photodetectors?
More interestingly, with increasing the asymmetric ratio (the width of wide fingers : the width of narrow fingers) of the interdigitated electrodes, the responsivity of the ZnO self-powered UV photodetectors was enhanced obviously, reaching as high as 20 mA W −1 when the asymmetric ratio was 20 : 1.
What is the frequency response of a photodetector?
In general, the responsivity of a photodetector may strongly depend on the modulation speed of the optical signal; this frequency response is a very important measure of the photodetector property.
What is the value of responsivity ℜ?
Ideally, the value of responsivity ℜ should be a constant, but in practice, ℜ can be a function of both signal wavelength and signal optical power.