What is PN junction 5 and what is PN junction

PN junction

Using different doping processes, through diffusion, p-type semiconductors.

It is made on the same semiconductor (usually silicon or germanium) substrate as n-type semiconductors, and at their intersection a space charge region called a pn junction is formed. The PN junction is unidirectionally conductive. P is the abbreviation of positive, and n is the abbreviation of negative, indicating the characteristics of the positive load and the load on the function.

When a single crystal semiconductor is doped with a p-type semiconductor with an acceptor impurity and an n-type semiconductor with a donor impurity, the transition zone near the interface between the p-type semiconductor and the n-type semiconductor is called the pn junction. PN junctions have homojunctions and heterojunctions.

Both. with the same semiconductor material.

The PN junction made of it is called a homojunction, and the PN junction made of two semiconductor materials with different bandgap widths is called a heterojunction. See also:

What is a PN knot? Why is it only one-way trafficking? The principle of power generation of solar cells (below).

p is an abbreviation for positive and n is an abbreviation for negative.

A simple explanation of the p-type junction: A semiconductor device composed of p-type and n-type semiconductor materials, the part (transition zone) where the p-type and n-type semiconductor materials are combined with each other is called the p-n junction.

A simple explanation of p-type semiconductor materials: in "monocrystalline silicon" materials, a small amount of trivalent elements are incorporated through a special process to form "positively charged holes" (positive charges) inside the monocrystalline silicon;

A simple explanation of n-type semiconductor materials: In the "monocrystalline silicon" material, a small amount of pentavalent elements is incorporated through a special process to form "negatively charged free electrons" (negative charges) inside the monocrystalline silicon.

As for what are trivalent elements and pentavalent elements, please refer to the relevant chemical information and will not repeat them here.

A simple explanation of the process of pn junction formation:

P-type materials have a majority of movable positive charges and a few fixed negative charges (negative ions); N-type materials have a majority of movable negative charges and a small number of fixed positive charges (positive ions).

When p-type and n-type materials come into contact, through the junction, the positive charge diffuses from the p-type semiconductor to the n-type semiconductor, and the negative charge diffuses from the n-type semiconductor to the p-type semiconductor. The positive charge and the negative charge meet and combine, and the original positive and negative charges (carriers) disappear. Therefore, there is a distance in the region near the junction (junction region) where there is a lack of positive or negative charge (carriers), but there is a charged fixed charge (immobile "negative ions" or immobile "positive ions") distributed in this region, which is called the space charge region.

The "negative ions" on the side of the p-type semiconductor that do not participate in diffusion, and the "positive ions" on the side of the n-type semiconductor that do not participate in diffusion, generate an electric field in the space charge region, and this electric field prevents the carriers from further diffusion and reaches equilibrium.

The PN junction is a very important structure in semiconductorsUsing different doping processes, p-type semiconductors and n-type semiconductors are fabricated on the same semiconductor (usually silicon or germanium) substrate through diffusion, and a space charge region is formed at their interface.

It can be seen from the formation principle of the P-N junction that in order for the P-N junction to be conductive to form a current, the resistance of the internal electric field in the space charge region must be eliminated. Obviously, adding a larger electric field in the opposite direction, that is, connecting the positive electrode of the external power supply in the P region and the negative electrode in the N region, can cancel out its internal self-built electric field, so that the carriers can continue to move, thus forming a linear forward current.

The applied reverse voltage is equivalent to a greater resistance of the built-in electric field, and the p-n junction cannot be turned on, and there is only a very weak reverse current (formed by the drift movement of a few carriers, and the current is saturated due to the limited number of few carriers).

When the reverse voltage increases to a certain value, due to the increase in the number and energy of the few tons, it will collide and destroy the internal covalent bonds, so that the originally bound electrons and holes will be released, and the current will continue to increase, and eventually the PN junction will be broken down (become a conductor) and damaged, and the reverse current will increase sharply. Fierce locust.

Formation of PN knots:

After the combination of p-type semiconductors and n-type semiconductors, since the free electrons in the n-type region are many, and the holes are almost zero, they are called few, while the holes in the p-type region are many, and the free electrons are few, and there is a concentration difference between electrons and holes at their junction. Due to the difference in the concentration of free electrons and holes, some electrons diffuse from the n-type region to the p-type region, and some holes have to diffuse from the p-type region to the n-type region.

As a result of their diffusion, one side of the p-region loses holes, leaving negatively charged impurity ions, and the n-region loses electrons, leaving behind positively charged impurity ions. The ions in the semiconductor in the open circuit cannot move arbitrarily and hence do not participate in conduction. These immovable charged particles form a space charge region near the interface between the p and n regions, and the thickness of the space charge region is related to the concentration of dopants.

Using different doping processes, p-type semiconductors and n-type semiconductors are made on the same semiconductor (usually silicon or germanium) substrate through diffusion, and a space charge region is formed at their interface, which is called pn junction. The PN junction is unidirectionally conductive and is the material basis of many devices in electronic technology, such as semiconductor diodes and bipolar transistors.

The p-n junction is composed of an n-type doped region and a p-type doped region in close contact, and its contact interface is called the metallurgical junction interface. [3]

On a complete silicon wafer, different doping processes are used to form n-type semiconductors on one side and p-type semiconductors on the other, and we call the area near the interface of two semiconductors p-n junctions.

When p-type semiconductors and n-type semiconductors are combined, there is a difference in carrier concentration at the interface, so that both electrons and holes have to diffuse from the place where the concentration is high to the place where the concentration is low. However, both electrons and holes are charged, and as a result of their diffusion, the original electrically neutral conditions in the p- and n-regions are destroyed. One side of the p-region is left with immovable negative ions due to the loss of holes, and one side of the n-region is left with immovable positive ions due to the loss of electrons.

These immovable charged particles are often referred to as space charges, and they are concentrated near the interface between the p-region and the n-region, forming a very thin space-charge region, which is what we call the p-n junction.

What is a PN knot? That is, when p-shaped semiconductors and n-shaped semiconductors are made together, p-shaped semiconductors are electropositive, while n-shaped semiconductors are electronegative. The holes in the p-shaped semiconductor will diffuse to the n-shaped semiconductor, and the electrons in the n-shaped semiconductor will diffuse to the p-shaped semiconductor, thus forming a space charge region.

Physics textbooks say that positive connection weakens the internal electric potential generated by the p-n junction, so it can be energized. My understanding: the electrons coming out of the negative pole of the power supply squeeze the relatively free electrons in the n segment of the semiconductor to the control range of the next atom, and the relatively free electrons carried by the next atom are squeezed into the control range of the next atom, and so on, this process develops until the electrons come to the holes located in the n segment formed due to the diffusion effect, and the electrons fill in the holes, forming the form I drew in the figure above, which is a semiconductor without pn junctions, and then the power supply continues to energize. The electrons come to the holes located at the p-terminus, and the holes are filled one by one, and when the holes at the p-terminal are filled, the electrons return to the positive pole of the power supply, so that a current is formed, (Question 1) Is my understanding correct?

See the following figure of my diagram for reverse energization, the electrons come out from the negative pole to the p-terminal of the semiconductor and fill in the holes, and the potential energy formed by the positive pole of the power supply sucks the electrons located at the n-terminal of the semiconductor, the p-terminal holes are filled, and the n-terminal electrons are drained. In this way, the original p-terminus becomes a new n-terminus because the holes are filled, and the original n-terminus is drained due to electrons (free electrons, the n-terminus is the n-terminal electron) to form a new p-terminus, and that becomes the top image of the diagram I drew? Wouldn't that also be able to conduct electricity?

There must be a serious error in my understanding, please answer your questions.

What is a PN knot is described below:

Using different doping processes, p-type semiconductors and n-type semiconductors are fabricated on the same semiconductor (usually silicon or germanium) substrate through diffusion, and a space charge region called pn junction is formed at their interface.

The PN junction is unidirectionally conductive. p is the abbreviation of positive, and n is the abbreviation of negative, indicating the characteristics of the positive load and the load on the function.

When a single crystal semiconductor is doped with a p-type semiconductor with an acceptor impurity and an n-type semiconductor with a donor impurity, the transition zone near the interface between the p-type semiconductor and the n-type semiconductor is called the pn junction. There are two types of PN junctions: homojunction and heterojunction. A PN junction made of the same semiconductor material is called a homojunction, and a PN junction made of two semiconductor materials with different bandgap widths is called a heterojunction.

The methods of manufacturing PN junctions include alloy method, diffusion method, ion implantation method and epitaxial growth method. Heterojunctions are usually fabricated by epitaxial growth.

P-type semiconductor (P refers to positive, positively charged): It is composed of a small amount of trivalent elements doped with a single crystal silicon through a special process, which will form positively charged holes inside the semiconductor;

N-type semiconductor (n refers to negative, negatively charged): It is composed of monocrystalline silicon mixed with a small amount of pentavalent elements through a special process, which will form negatively charged free electrons inside the semiconductor.

In p-type semiconductors, there are many positively charged holes and negatively charged ionized impurities. Under the action of an electric field, the holes are movable, while the ionized impurities (ions) are immobile. There are many movable negative electrons and fixed positive ions in n-type semiconductors.

When p-type and n-type semiconductors come into contact, holes near the interface diffuse from p-type semiconductors to n-type semiconductors, and electrons diffuse from n-type semiconductors to p-type semiconductors.

Holes and electrons meet and reunite, and carriers disappear. Because there is a lack of carriers in the junction region near the interface, there are charged fixed ions distributed in space, which is called the space charge region.

Objects such as germanium, silicon, selenium, gallium arsenide, and many metal oxides and metal sulfides, whose conductivity is between conductors and insulators, are called semiconductors.

Semiconductors have some special properties. For example, the relationship between the resistivity and temperature of semiconductors can be used to make thermistors (thermistors) for automatic control; Its photosensitive and special round digging properties can be used to make photosensitive elements for automatic control, such as photocells, photocells and photoresistors.

Semiconductors also have one of the most important properties, and if trace impurities are properly incorporated into pure semiconductor substances, their conductivity will increase millions of times. This characteristic can be used to manufacture a variety of semiconductor devices for different purposes, such as semiconductor diodes, transistors, etc.

If one side of a semiconductor is made into a p-shaped region and the other side is made into an n-shaped region, a thin layer with special properties is formed near the junction, which is generally called a pn junction. The upper part of the figure shows the diffusion of carriers on both sides of the interface between p-type semiconducting orange refractory and n-type semiconductors (indicated by black arrows). The middle part shows the formation process of the p-n junction, indicating that the diffusion of the carriers is greater than the drift (indicated by a blue arrow, and a red arrow indicates the direction of the built-in electric field).

The lower part is the formation of the PN junction. Represents the dynamic equilibrium of diffusion and drift.