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How sensitive is a photodiode?
Photodiodes made from different materials (silicon, germanium, indium gallium arsenide phosphide, or indium gallium arsenide) have varying levels of sensitivity as well as differing speeds and dark current. Silicon, for example, provides sensitivity for wavelengths between ~400 and 1000 nm.
How do you calculate responsivity of a photodiode?
where h ν is the photon energy, η is the quantum efficiency, and e the elementary charge. For example, a silicon photodiode with 90% quantum efficiency at a wavelength of 800 nm, the responsivity would be ≈ 0.58 A/W.
What is photodiode response time?
Photodiode response time is the root mean square sum of the charge collection time and the RC time constant arising from series plus load resistances and the junction and stray capacitances. Charge collection time is voltage dependent and is made up of a fast and a slow component.
What is the responsivity of a photodiode?
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.
How is the sensitivity of a photodiode determined?
Definition : The sensitivity of a photodiode is the ratio of amount of current flow with unit light irradiance. It can expressed as per equation below. The dark current can be minimized in order to enhance the sensitivity of the photodiode. Following equation or formula is used for Photodiode sensitivity calculator .
What is the responsivity of a silicon photodiode?
Definition : The responsivity of silicon photodiode is a measure of sensitivity to light. It is defined as ratio of photocurrent (I p) to incident light power P at given wavelength. Responsivity, R λ = I p /P In other words, it is measure of the effectiveness of conversion of light power into electric current.
Why is a photodiode used to measure diffused light?
If you are trying to measure a diffused light source, then a larger area device will capture more light. More light equals more signal. The other option is to focus the light source on a small area if possible — then a smaller photodiode could be used.
What are the characteristics of a photodiode with no incident light?
Photodiode Characteristics n I-V CHARACTERISTICS The current-voltage characteristic of a photodiode with no incident light is similar to a rectifying diode. When the photodiode is forward biased, there is an exponential increase in the current. When a reverse bias is A 2. photodiodes. Photodiode Characteristics