Now, if we join the two types of semiconductors ptype and ntype together then a new device is formed called as pn junction diode. A diode is formed by joining two equivalently doped ptype and ntype semiconductor. Pn junction diode applications pn diode applications. Holes are the majority carriers and electrons are the minority carriers. A pn junction diode is twoterminal or twoelectrode semiconductor device, which allows the electric current in only one direction while blocks the electric current in opposite or reverse direction. When they are joined an interesting phenomenon takes place. When the diode is forwardbiased, it can be used in led lighting applications.
As shown in the figure, pn junction diode is a 2 terminal polarity sensitive device. If we join a piece of p type material to a pieceof n type material such that the crystalstructure remains continuous at the boundary, a pn junction is formed 2. Semiconductor physics semiconductors and diodessemiconductors. These materials are ntype, having electrons are majority carrier and ptype material, having holes are majority carrier. Apr 05, 2019 working of pn junction diode if an external potential is applied to the terminals of pn junction, it will alter the potential between the p and nregions.
If the positive terminal of the battery is connected to the ptype semiconductor and the negative terminal of the battery is connected to the ntype semiconductor, the diode is said to be in forward bias. Pn junction tutorial introduction to pn junction diodes. Abrupt depletion layer approximation let apply bias and calculate current through the pn junction currents in pn junction from sze, 1981. The pn junction is a versatile element, which can be used as a. A pn junction diode is formed by doping one side of a piece of silicon with a ptype dopant boran and the other side with a ntype dopant phosphorus. This page of application notes section covers pn junction diode applications. A pn junction diode is a twoterminal electronics element, which can be classified as either. Since a junction forms between a p type and n type material it is called as pn junction.
A pn junction is a boundary or interface between two types of semiconductor materials, ptype and ntype, inside a single crystal of semiconductor. With proper biasing, pn diode allows current to flow in single direction. In this type of diode, we dope one side of a semiconductor piece with an acceptor impurity and another side with a donor impurity. They are also called pn diodes in analogy with vacuum diodes. Pn junctions consist of two semiconductor regions of opposite type. Semiconductor pn junction diodes physically, diodes are formed by the interface between two regions of oppositely doped semiconductor i. The load resistance r l is connected to these terminals through a pn junction diode d. P type and n type semiconductors, takenseparately are of very limited use. After having known about various components, let us focus on another important component in the field of electronics, known as a diode. Pn junction tutorial varactor diode construction, working, different types of semiconductor devices what is signal diode. In normal pn junction diodes, silicon is most widely used because it is less sensitive to the temperature. The pn junction diode is a twoterminal device, which is formed when one side of the pn junction diode is made with ptype and doped with the ntype material. In this video you will learn about the construction of a pn junction diode, working of it and the characteristics of it under forward and reverse.
Construction, working and characteristics of a pn junction diode. Najmabadi, ece65, winter 2012 high concentration of h on the p side holes diffuse towards the junction high concentration of e on the n side electrons diffuse towards the junction n side is positively charged because it has lost electrons. The pn junction is the root for semiconductor diodes. Normally the voltage is taken along the xaxis and current along yaxis.
By exploring the electrical properties of silicon, it is possible to acquire an understanding of the inner workings of the pn junction. In a grown junction method the earliest technique used, intrinsic semiconductor material and ptype impurities are placed in a quartz container and heated until. The pnjunction obey the ohms law whereas zener diode does not obey the ohms law. The word diode can be explained as di means two and ode is obtained from electrode. The pn junction solidstate device theory electronics. It is one of the simplest semiconductor devices as it allows current to flow in only one direction. We can then fill in the junction region of the band diagram as. Although it is not discussed majorly outside the concept of pn junction diode and sometimes the transistor, a pn junction is an essential topic in semiconductor electronics. Jan 16, 2018 pn junction diode is a device made of two semiconductor material joined together with the required amount of impurity. In the positive half cycle, during the time interval 0 to t2, diode d will be forward biased and conduct, i. A pn junction with open terminals excluding minority carriers f. Diode construction techniques the pn junction of a diode may be one of three types.
Pnjunction diode and diode circuits 1 main properties of semiconductors 2 the pnjunction in equilibrium 3 the i v characteristics of the pnjunction 4 deviations from the ideal diode 5 analysis of the diode circuits 6 rectifier circuits. The construction of led is similar to the normal pn junction diode except that gallium, phosphorus and arsenic materials are used for construction instead of silicon or germanium materials. So, in this pn junction tutorial, we will discuss some of the basics of a pn junction, how a pn junction is formed, characteristics of pn junction and many other aspects. A pn junction is the metallurgical boundary between the n and pregions of a semiconductor crystal. The p positive side contains an excess of holes, while the n negative side contains an excess of electrons in the outer shells of the electrically neutral atoms there. Such junctions show a pronounced rectifying behavior.
Jan 29, 2019 pn junction diode is one of the fundamental elements in electronics. Forward bias current flows reverse bias no current flow. This pn diode applications are very useful for beginners. Definition, symbol, and types of diodes electrical4u. A pnjunction diode is formed when a ptype semiconductor is fused to an ntype semiconductor creating a potential barrier voltage across the diode junction. Silicon a single silicon atom consists of fourteen negatively.
It is the most essential and the basic building block of the electronic device. The diode conducts when forward bias is applied and it will introduce zero resistance in the circuit. The pn junction is the fundamental building block of the electronic age. Lecture 16 the pn junction diode ii equivalent circuit model november 3, 2005 contents. Silicon pn junction diodes have a junction potential of about 0. Jan 04, 2020 a pn junction is the simplest form of the semiconductor diode. The pn junction is of great importance as it is the main control element for the semiconductor devices. In ideal conditions, this pn junction behaves as a short circuit when it is forward biased, and as an open circuit when it is in the reverse biased. The potential at terminal x with respect to y will vary as a sine function with time. Pn junction diode is a device made of two semiconductor material joined together with the required amount of impurity.
The pn junction is an interface between a ptype and an ntype region and is used to construct diodes and transistors. Jan 21, 2019 what is a pn junction when a ptype semiconductor is suitably joined to an ntype semiconductor, the contact surface is called pn junction. Pnjunction diode characteristics ppt documentation. If the diode is forward biased, it allows the electric current flow. In a ptype semiconductor, the number p p of holes is much larger than the number of electrons n p p p n p. This potential difference can alter the flow of majority carriers, so that the pn junction can be used as an opportunity for the diffusion of electrons and holes.
You just need to take a battery whose values can be varied from o to v volts, connect its positive terminal to the pside of pn junction diode and then connect the negative terminal of battery to the nside of the pn junction diode. A pn junction diode is formed when a ptype semiconductor is fused to an ntype semiconductor creating a potential barrier voltage across the diode junction the effect described in the previous tutorial is achieved without any external voltage being applied to the actual pn junction resulting in the junction being in a state of equilibrium. Pn junction diode and characteristics of pn junction diode. Working of pn junction diode with biasing, characteristics. Pn junction diode baising and its vi characteristics elprocus. Voltampere vi characteristics of a pn junction or semiconductor diode is the curve between voltage across the junction and the current through the circuit. Semiconductor electronicsdiodeconstruction and operation. Image source forward biasing a pn junction diode is very simple. The ohms law said that the voltage applies across the diode is equal to the product of the current and resistance applied across the diodes. Most semiconductor devices contains one or more pn junctions. A semiconductor diode is a two terminal electronic component with a pn junction.
From the above, it follows that zero power dissipation occurs in an ideal diode. A diode consists of a single pn junction, figure 68. Jan 21, 2019 vi characteristics of pn junction diode. Vi characteristics of pn junction diode electronics post.
The pn junction biasing the pn junction the diode trouble shooting. The recombination at the junction allows battery current to flow through the pn junction diode. On the other hand, if the diode is reverse biased, it blocks the. Pn junction diode baising and its vi characteristics. Investigation of a barrier layer by the thermoprobe method pdf. No generationrecombination in the depletion layer 6.
A pn junction is a boundary or interface between two types of semiconductor materials, ptype. This is the basic construction of the pn junction diode. Semiconductor, silicon, pn junction, forward bias, reverse bias, diode. The anode which is the positive terminal of a diode is represented with a and the cathode. A diode is a tiny electronic component used in almost all the electronic circuits to enable the flow of current in only one direction. Pn junction diode in the reversebiased configuration is sensitive to light from a range between 400nm to nm, which includes visible light. Vi characteristics of pn junction diode in 3biasing modes. Light emitting diode led working, construction and. The name diode is derived from diode which means a device that has two electrodes. The pnjunction diode is mainly used for rectification purpose, whereas the zener diode is used for providing the. Formation of pn junction in actual practice, a pn junction will not be formed if a ptype.
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