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प्रश्न
Write the two processes that take place in the formation of a p-n junction.
Name two important processes involved in the formation of a p-n junction diode.
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उत्तर
The processes of "diffusion" and "drift" are critical in a p-n junction. When the p and n-sides come into contact, the majority of carriers "diffuse" from a high concentration to a low concentration. Electrons move and combine with holes from the n-side to the p-side. Holes migrate from the p-side to the n-side in the same way that electrons and holes do at the junction. A "depletion region" is formed when the near junction area runs out of carriers and becomes charged. Current "diffusion" is caused by current "diffusion."
In the depletion area, the charge produces an electric field. The electric field creates a flow of minority carriers in the 'depletion' region. The produced current is known as "drift current," and it is referred to as drift. The directions of "diffusion and drift current" are reversed.
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संबंधित प्रश्न
In a p-n junction diode, the current I can be expressed as
I = `"I"_0 exp ("eV"/(2"k"_"BT") - 1)`
where I0 is called the reverse saturation current, V is the voltage across the diode and is positive for forward bias and negative for reverse bias, and I is the current through the diode, kBis the Boltzmann constant (8.6×10−5 eV/K) and T is the absolute temperature. If for a given diode I0 = 5 × 10−12 A and T = 300 K, then
(a) What will be the forward current at a forward voltage of 0.6 V?
(b) What will be the increase in the current if the voltage across the diode is increased to 0.7 V?
(c) What is the dynamic resistance?
(d) What will be the current if reverse bias voltage changes from 1 V to 2 V?
A zener diode is fabricated by heavily doping both p- and n- sides of the junction. Explain, why?
Explain, with the help of a circuit diagram, the working of n-p-n transistor as a common emitter amplifier.
How is a zener diode fabricated so as to make it a special purpose diode? Draw I-V characteristics of zener diode and explain the significance of breakdown voltage.
Explain briefly, with the help of a circuit diagram, how a p-n junction diode works as a half wave rectifier.
A hole diffuses from the p-side to the n-side in a p-n junction. This means that
The potential barrier existing across an unbiased p-n junction is 0.2 volt. What minimum kinetic energy a hole should have to diffuse from the p-side to the n-side if (a) the junction is unbiased, (b) the junction is forward-biased at 0.1 volt and (c) the junction is reverse-biased at 0.1 volt?
What are the readings of the ammeters A1 and A2 shown in figure. Neglect the resistance of the meters.
(Assume that the resistance of each diode is zero in forward bias and is infinity in reverse bias.)
An AC source is connected to a diode and a resistor in series. Is the current thorough the resistor AC or DC?
The depletion layer in the p-n junction diode is caused by ______.
Zener breakdown occurs in a p-n junction having p and n both:
