What is the meaning of sensitivity of photo diode?

Definition: The sensitivity of a photodiode is the ratio of amount of current flow with unit light irradiance. The dark current can be minimized in order to enhance the sensitivity of the photodiode.

Which photodiode has highest sensitivity?

Silicon photodiodes
Silicon photodiodes are the most commonly used and, as shown in Fig. 7.3, have peak sensitivity around 0.8–0.9 μm. Germanium and InGaAs photodiodes are useful in the region from 1.1 to 1.7 μm.

In which bias photo diode is sensitive?

This reduces the overall noise current of the system. Thus unbiased P-N or PIN photodiodes are better suited for low light level applications compared to operation with reverse voltage bias. (The reverse biased APD will still provide a higher sensitivity than P-N or PIN photodiodes for low light applications.)

What is sensitivity of diode?

The diode achieved a level of sensitivity more than ten times higher than conventional Schottky barrier diodes, according to the researchers. …

Why a photo diode is reverse biased?

The photodiode is reverse biased for operating in the photoconductive mode. As the photodiode is in reverse bias the width of the depletion layer increases. This reduces the junction capacitance and thereby the response time. In effect, the reverse bias causes faster response times for the photodiode.

How do you increase the sensitivity of a photodiode?

In the new approach sensitivity is allowed to increase as ambient light/noise decreases. With gain fixed at a high value, the new circuit varies the current through the photodiode using a current mirror circuit to allow the photodiode itself greater sensitivity when it requires less current to counteract ambient light.

Why photodiode is reverse biased?

Is photo diode heavily doped?

PIN photodiode operation. A PIN photodiode is made of p region and n region separated by a highly resistive intrinsic layer. The intrinsic layer is placed between the p region and n region to increase the width of depletion region. The p-type and n-type semiconductors are heavily doped.

Why do we use Zener diode?

Because of this property, Zener diodes are widely used as constant-voltage devices. A Zener diode permits Zener current, Iz, to flow when the voltage is above the specified Zener voltage. Thus, a Zener diode can be used for voltage detection by sensing Zener current with some other device.

What is the use of diode in reverse biased?

Reverse bias usually refers to how a diode is used in a circuit. If a diode is reverse biased, the voltage at the cathode is higher than that at the anode. Therefore, no current will flow until the electric field is so high that the diode breaks down.

What are the characteristics of a photo IC diode?

It also has good linearity characteristics. Table 1 shows the photo IC diode lineup. When clas- sified by spectral response, there are two types avail- able: infrared and visual-sensitive compensation. The visual-sensitive compensation type provides a spectral response close to human eye sensitivity without a visual-sensitive compensation filter.

What is the peak sensitivity of a photodiode?

The sensitivity of a photodiode is normally quoted in A/W. This curve shows the output current versus light power density for the Osram SFH203. Peak sensitivity is 0.62A/W so you can see 0.06µA at 10µW/cm2. It is a straight line because the relationship is linear.

Why do you need a photodiode for a diffused light source?

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. The sensitivity of a photodiode is normally quoted in A/W.

Can a photodetector be sensitive to all 3 colors?

The photodetector must, of course, be sensitive to all of the (3) used light colors. The photodetector may need some time to stabilize after switching LEDs before accurate readings can be obtained; photoresistors, for instance, are usually relatively slow.