Does voltage affect the depletion region?

Does voltage affect the depletion region?

Under reverse bias (applying a negative voltage to the P-side with respect to the N-side), the potential drop (i.e., voltage) across the depletion region increases. Essentially, majority carriers are pushed away from the junction, leaving behind more charged ions.

Why does the width of the depletion region increase with the increase in applied voltage?

The positive terminal of the external battery attracts the majority carrier electrons from the n-region and its negative terminal attract the majority carrier holes from p-region. Due to it, the majority charge carriers move away from the junction. This increases the width of the depletion layer.

Why does depletion region increases in reverse bias?

A P-N junction diode is formed by joining one P-type and one N-type diode. This happens because when we apply reverse bias voltage the electrons are drifted away from the junction and hence, conduction is not possible. So, the width of the depletion region in a P-N junction diode is increased by reverse bias.

What causes the depletion region?

The depletion region is caused by the diffusion of charges. The holes and the electrons diffusing towards each other combine near the junction. In doing so positive and negative ions are formed. The pair of positive and negative ions at the junction forms the dipole.

How does the depletion region behave?

In the depletion region, an electric field exists that quickly sweeps out electron-hole pairs that may be thermally generated and reduces the equilibrium concentration of the charge carriers to exceedingly low levels. This region, called the depletion layer, behaves as an insulator.

What is the width of a depletion region?

The physical width of the depletion region in a typical Si diode ranges from a fraction of a micrometer to tens of micrometers depending on device geometry, doping profile, and external bias.

Why is the width of depletion region fixed?

The width of depletion region is depends on the amount of impurities added to the semiconductor. Impurities are the atoms (pentavalent and trivalent atoms) added to the semiconductor to improve its conductivity. If pentavalent atoms are added to the pure or intrinsic semiconductor, an n-type semiconductor is formed.

What is width of depletion region?

Does the reverse diode current depends on voltage?

The current flows effortlessly while in forward bias, but reverse bias does not permit current to flow through the diode. The level of the current depends on the forward voltage while in forward bias, however, the amount of current is minimal or negligible in reverse bias.

Does current flow in reverse bias?

5.1. 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.

How does the depletion region form in a PN junction?

At the instant of doping, free electrons near the junction from the N-type region pass the joining point toward the P-type region and combine with a hole near the junction. As the N-type region losses electrons and P-type regions lose holes, so they are not electrically neutral.

Why does the depletion zone get larger in reverse bias?

The electric field in the depletion region becomes smaller, and the potential difference decreases (over a smaller depletion region). If the forward-bias potential difference increases yet more, eventually the depletion region disappears altogether, so there’s nopoorly-conducting region.

Why is the depletion region of a junction in equilibrium?

(b) pn -junction charge density profile. The potential difference that now exists in the depletion region will prevent the further flow of majority carriers, so the junction will be in equilibrium, with equal amounts of charge existing on both sides.

What does reverse bias on a PN junction mean?

Reverse bias on a pn junction means that a negative potential is applied to the p side and a positive potential to the n side. The negative potential draws the holes toward the electrode, away from the depletion region.