AnswersDriveDepletion region or depletion layer is a region in a P-N junction diode where no mobile charge carriers are present. Depletion layer acts like a barrier that opposes the flow of electrons from n-side and holes from p-side.
Accordingly, how is depletion region formed in pn junction?
Depletion Region. When a p-n junction is formed, some of the free electrons in the n-region diffuse across the junction and combine with holes to form negative ions. In so doing they leave behind positive ions at the donor impurity sites.
What is a potential barrier in pn junction diode?
As more electrons and holes flow in the depletion region the number of positive and negative ions is reduced, causing the depletion region to narrow. The energy loss in overcoming the barrier potential results in a voltage drop across the PN junction equal to the barrier potential. ( 0.7V for Si, 0.3V for Ge.)
1
What is cut off region in transistor?
The transistor is operated in this mode, when it is used as a closed switch. Cut- off Region:- Emitter-Base junction is reverse biased. Collector- base junction is reverse biased. In this region both the junctions are Reverse Biased.
2
How does the diode work?
N-type silicon (red) has extra electrons (black). Battery connected across the p-n junction makes the diode forward biased, pushing electrons from the n-type to the p-type and pushing holes in the opposite direction. Electrons and holes cross the junction and combine.
3
What is meant by break down voltage in pn junction diode?
The maximum reverse bias voltage that can be applied to a p-n diode is limited by breakdown. Breakdown is characterized by the rapid increase of the current under reverse bias. The corresponding applied voltage is referred to as the breakdown voltage. The breakdown voltage is a key parameter of power devices.
4
What is the definition of barrier voltage?
"The barrier voltage is the amount of electromotive force required to start current through the P-N junction. Barrier voltages for silicon typically range from 0.5 - 0.7 volts. Barrier voltages for germanium typically range from 0.2 - 0.3 volts. "
5
How the depletion region is formed?
Depletion Region. When a p-n junction is formed, some of the free electrons in the n-region diffuse across the junction and combine with holes to form negative ions. In so doing they leave behind positive ions at the donor impurity sites.
6
What is the cut in voltage?
There is a definite forward voltage at which the diode starts to conduct significantly. This is called the knee voltage or cut-in voltage and is equal to the barrier potential of the p-n junction.
7
What is the depletion region?
Depletion region or depletion layer is a region in a P-N junction diode where no mobile charge carriers are present. Depletion layer acts like a barrier that opposes the flow of electrons from n-side and holes from p-side.
8
What is a potential barrier in pn junction diode?
As more electrons and holes flow in the depletion region the number of positive and negative ions is reduced, causing the depletion region to narrow. The energy loss in overcoming the barrier potential results in a voltage drop across the PN junction equal to the barrier potential. ( 0.7V for Si, 0.3V for Ge.)
9
What is meant by depletion region?
In semiconductor physics, the depletion region, also called depletion layer, depletion zone, junction region, space charge region or space charge layer, is an insulating region within a conductive, doped semiconductor material where the mobile charge carriers have been diffused away, or have been forced away by an
10
How a pn junction can be formed?
P-n junctions are formed by joining n-type and p-type semiconductor materials, as shown below. Since the n-type region has a high electron concentration and the p-type a high hole concentration, electrons diffuse from the n-type side to the p-type side.
11
What is the cause of Zener breakdown?
It occurs in a reverse biased p-n diode when the electric field enables tunneling of electrons from the valence to the conduction band of a semiconductor, leading to a large number of free minority carriers which suddenly increase the reverse current. The I-V curve for a diode showing avalanche and Zener breakdown.
12
What do you mean by knee voltage?
Knee voltage is also known as “cut-in-voltage". The minimum amount of voltage required for conducting the diode is known as “knee voltage” or “cut-in-voltage". And also said as The forward voltage at which the current through PN junction starts increasing rapidly is known as knee voltage.
13
What do you mean by reverse bias?
reverse bias The applied d.c. voltage that prevents or greatly reduces current flow in a diode, transistor, etc. For example, a negligible current will flow through a diode when its cathode is made more positive than its anode; the diode is then said to be reverse biased. Compare forward bias. "reverse bias."
14
What is meant by a potential barrier?
The potential barrier in the pn junction is the barrier which does not allow charge flow across the junction normally. Normally in a pn junction the value of barrier potential is typically 0.3-0.7V. Depending upon the material used.
15
What is the breakdown region of a diode?
For a typical diode, the breakdown mechanism is also called avalanche breakdown. In reverse bias below breakdown voltage, the current is due to generation of carriers (recombination-generation current) in the depletion region and carriers get across the depletion region with the help of the electric field.
16
What is a PN junction?
The PN junction is one of the primary building blocks of semiconductors. Diodes and Thyristors. A diode (one way valve) is a PN junction with p-type on one side and n-type on the other.
17
What is a PN junction diode?
An external voltage which decreases the potential barrier is said to act in the “Forward Bias” direction. There are two operating regions and three possible “biasing” conditions for the standard Junction Diode and these are: Zero Bias – No external voltage potential is applied to the PN junction diode.
18
What is the meaning of breakdown voltage?
For diodes, the breakdown voltage is the minimum reverse voltage that makes the diode conduct in reverse. The breakdown voltage of an insulator is the minimum voltage that causes a portion of an insulator to become electrically conductive.
19
What is the breakdown voltage of a diode?
The breakdown voltage of an insulator is the minimum voltage that causes a portion of an insulator to become electrically conductive. For diodes, the breakdown voltage is the minimum reverse voltage that makes the diode conduct appreciably in reverse.
20
What is mobile charge carriers?
Charge carrier. In metals, the charge carriers are electrons. One or two of the valence electrons from each atom is able to move about freely within the crystal structure of the metal. The free electrons are referred to as conduction electrons, and the cloud of free electrons is called a Fermi gas.