Holes are the majority carriers and electrons are the minority carriers. 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. Image source forward biasing a pn junction diode is very simple. A pn junction is the metallurgical boundary between the n and pregions of a semiconductor crystal. The pn junction is the root for semiconductor diodes. Now, if we join the two types of semiconductors ptype and ntype together then a new device is formed called as pn junction diode. The pn junction is an interface between a ptype and an ntype region and is used to construct diodes and transistors.
These materials are ntype, having electrons are majority carrier and ptype material, having holes are majority carrier. A diode consists of a single pn junction, figure 68. Pn junction diode in the reversebiased configuration is sensitive to light from a range between 400nm to nm, which includes visible light. 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. The pn junction solidstate device theory electronics. As shown in the figure, pn junction diode is a 2 terminal polarity sensitive device. By exploring the electrical properties of silicon, it is possible to acquire an understanding of the inner workings of the pn junction. The anode which is the positive terminal of a diode is represented with a and the cathode. Pn junction diode construction working and uses electrical. 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. 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. The word diode can be explained as di means two and ode is obtained from electrode. Jan 04, 2020 a pn junction is the simplest form of the semiconductor diode. In this type of diode, we dope one side of a semiconductor piece with an acceptor impurity and another side with a donor impurity.
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. 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. Light emitting diode led working, construction and. Lecture 16 the pn junction diode ii equivalent circuit model november 3, 2005 contents. A pn junction diode is a twoterminal electronics element, which can be classified as either. 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. Jan 29, 2019 pn junction diode is one of the fundamental elements in electronics. Pn junction diode baising and its vi characteristics. Formation of pn junction in actual practice, a pn junction will not be formed if a ptype. 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. Vi characteristics of pn junction diode in 3biasing modes. When the diode is forwardbiased, it can be used in led lighting applications.
The pn junction is a versatile element, which can be used as a. 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. P type and n type semiconductors, takenseparately are of very limited use. In normal pn junction diodes, silicon is most widely used because it is less sensitive to the temperature.
Semiconductor physics semiconductors and diodessemiconductors. With proper biasing, pn diode allows current to flow in single direction. The name diode is derived from diode which means a device that has two electrodes. Pn junctions consist of two semiconductor regions of opposite type. The load resistance r l is connected to these terminals through a pn junction diode d. Construction, working and characteristics of a pn junction diode. Pn junction tutorial varactor diode construction, working, different types of semiconductor devices what is signal diode. Semiconductor, silicon, pn junction, forward bias, reverse bias, diode. A semiconductor diode is a two terminal electronic component with a pn junction. No generationrecombination in the depletion layer 6.
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. 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. Since a junction forms between a p type and n type material it is called as pn junction. They are also called pn diodes in analogy with vacuum diodes. A pnjunction diode is formed when a ptype semiconductor is fused to an ntype semiconductor creating a potential barrier voltage across the diode junction.
Normally the voltage is taken along the xaxis and current along yaxis. A diode is formed by joining two equivalently doped ptype and ntype semiconductor. 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. 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. We can then fill in the junction region of the band diagram as. A pn junction is a boundary or interface between two types of semiconductor materials, ptype and ntype, inside a single crystal of semiconductor. In the positive half cycle, during the time interval 0 to t2, diode d will be forward biased and conduct, i.
Abrupt depletion layer approximation let apply bias and calculate current through the pn junction currents in pn junction from sze, 1981. This is the basic construction of the pn junction diode. Silicon a single silicon atom consists of fourteen negatively. A pn junction with open terminals excluding minority carriers f. The pn junction is the fundamental building block of the electronic age. It is the most essential and the basic building block of the electronic device. Pn junction diode is a device made of two semiconductor material joined together with the required amount of impurity.
The pnjunction obey the ohms law whereas zener diode does not obey the ohms law. Pn junction tutorial introduction to pn junction diodes. It is one of the simplest semiconductor devices as it allows current to flow in only one direction. If the diode is forward biased, it allows the electric current flow. Pnjunction diode characteristics ppt documentation. 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.
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. 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 diode is mainly used for rectification purpose, whereas the zener diode is used for providing the. Pn junction diode applications pn diode applications.
This pn diode applications are very useful for beginners. Forward bias current flows reverse bias no current flow. This page of application notes section covers pn junction diode applications. Definition, symbol, and types of diodes electrical4u. Pn junction diode baising and its vi characteristics elprocus. Diode construction techniques the pn junction of a diode may be one of three types. The pn junction biasing the pn junction the diode trouble shooting. From the above, it follows that zero power dissipation occurs in an ideal diode.
Silicon pn junction diodes have a junction potential of about 0. The diode conducts when forward bias is applied and it will introduce zero resistance in the circuit. When they are joined an interesting phenomenon takes place. In a ptype semiconductor, the number p p of holes is much larger than the number of electrons n p p p n p. Jan 21, 2019 vi characteristics of pn junction diode. Most semiconductor devices contains one or more pn junctions. A pn junction is a boundary or interface between two types of semiconductor materials, ptype. 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. Investigation of a barrier layer by the thermoprobe method pdf. Semiconductor pn junction diodes physically, diodes are formed by the interface between two regions of oppositely doped semiconductor i.
Working of pn junction diode with biasing, characteristics. 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. Such junctions show a pronounced rectifying behavior. Pn junction diode and characteristics of pn junction diode. Semiconductor electronicsdiodeconstruction and operation. After having known about various components, let us focus on another important component in the field of electronics, known as a diode.
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. The recombination at the junction allows battery current to flow through the pn junction diode. 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. The pn junction is of great importance as it is the main control element for the semiconductor devices. A diode is a tiny electronic component used in almost all the electronic circuits to enable the flow of current in only one direction. The potential at terminal x with respect to y will vary as a sine function with time. Jan 16, 2018 pn junction diode is a device made of two semiconductor material joined together with the required amount of impurity. On the other hand, if the diode is reverse biased, it blocks the. Vi characteristics of pn junction diode electronics post.
1078 1388 636 939 818 187 254 1316 1199 203 514 535 1323 170 1466 5 369 1455 1494 764 262 1104 1064 169 637 702 577 161 242 809 322 1230 792 1163 431 756 870 162 384 927 1214 845 853 372 28