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Why are photodiodes preferably used in reverse biasing?
Photodiodes convert incident light to electric current more effectively in reverse bias condition than in forward bias because the width of depletion region increases as you increase the applied reverse bias voltage across the diode (directly proportional) in a reverse biased pn junction.
Why are photodiodes preferably operated?
However, when you forward bias a pn junction, the width of the depletion region reduces, so, only a small portion of the incident photons get converted to electric current. Hence, are photodiodes preferably operated under reverse bias.
Which one of the following optoelectronic devices works under reverse bias conditions?
Photodiode
Photodiode is a device based on the principle of photovoltaic effect. When photons of energy greater than the band-gap falls on photodiode (p-n junction diode), it excites electron from the valence band to conduction band. It is used in reverse-bias.
What is the difference between solar cell and photodiode?
A photodiode, like a solar cell, is a photovoltaic semiconductor device. Photodiodes, however, are optimized for light detection while solar cells are optimized for energy conversion efficiency. Photodiodes are essentially identical to diodes since both consist of p-n junctions.
What happens when a photo diode is reverse biased?
When the diode is reversed biased, no ordinary current flows and the detection of the photo-current is much easier. When a photo-diode is reverse biased, the width of depletion layer increases as compared to forward biased and a small reverse current (dark current) flows through the diode.
Which is more significant in reverse bias current or photocurrent?
We can say that in reverse bias, diode changes the incident light to current, more significantly due to broad depletion layer i.e. photocurrent is significant in reverse bias as compared to the forward bias current. Was this answer helpful?
How to look at the reverse biased pn junction?
Another way to look at the reverse biased PN junction is a high field region (due to the dopant ions remaining through the reverse biased junctions). The moment you create a hole-electron pair from a photon, each of these charge carriers is rapidly separated and swept out of the depletion region to produce a photocurrent.
Why is the forward bias higher than the reverse bias?
Plus I think the forward bias current is much higher than the photocurrent generated. The reason only ehps generated in the depletion region (or very close to the depletion region) contribute to current is because those are the ehps that are in an electric field.