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Whenever two dissimilar conductors touch a "potential barrier" forms. All conductive materials have a voltage above zero that an electron must have to enter the material. In true conductors, this voltage is very low. In semiconductors, it can vary, but is usually in the 0.25 to 6.8 Volt range. In insulators, it can be very, very high. When two semiconductors or a metal and a semiconductor touch the difference is polarity sensitive. The higher the "band gap", the voltage that must be overcome to enter the "conduction band", the higher the voltage drop in the forward bias direction. Think of the "band gap", or potential barrier, as being like a curb on a road and sidewalk. It's easy to ride a bike off the sidewalk over the curb onto the road, but not so easy the other way.

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Why potential across pn junction is called potential barrier?

The potential across a pn junction is called potential barrier because majority charge carriers have to overcome this potential before crossing the junction.


When does a PN junction allows current to flow?

A PN junction allows current to flow when it is forward-biased, meaning the positive terminal of a voltage source is connected to the p-type material and the negative terminal to the n-type material. This reduces the barrier potential at the junction, allowing charge carriers (holes and electrons) to recombine and flow across the junction. In contrast, when the junction is reverse-biased, the barrier potential increases, preventing current flow.


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The built in potential in a pn junction. Due to the difference in carrier concentration between the sides of a pn junction. Diffusion potential increases with increase in doping levels.


What is the effect of temperature on barrier voltage in a pn junction diode?

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When light falls on the junction of a pn junction/diode the potential barrier gets break down due to majorty of electrons flow and they release energy in the form of light.


Why the depletion layer becomes very thick when then pn junction diode is lightly doped?

When the pn junction is forward biased,the height of the potential barrier is reduced allowing more majority charge carriers ti flow across the junction and when it is reversed biased, the height of the potential barrier increases there b reducing the majority charge carrier that have sufficient energy to flow across the junction.


What is potential barrier factor?

Potential barrier is the energy inserted in order to go against the passage of electron.


What is a barrier voltage?

The voltage across a forward-biased PN junction in a semiconductor diode or transistor.


Effect of temperature on pn-junction diodes?

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What are forward and reverse bias?

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What is forward and reversed biasing?

This is a characteristics of semiconductor diode {pn junction}.In forward biasing here we connect p to positive terminal and n -ve terminal when external voltage is aplied in such a direction that cancels out potential barrier thus permitting current flow In reverse biasing the connection of pn junction is inverted but in this the potential barrier incresesand offers resistance to current flow but at a certain voltage current increases suddenly(the break down voltage)the zener diode works in this principle


How a pn-junction can be formed?

A pn junction can be formed by bringing the p and n type materials together.