The ptype region has many holes, and the ntype region has many free electrons. To plot voltampere characteristics of silicon pn junction diode. However, both regions are electrically neutral before the pn. When the positive polarity is at the anode the diode is forward biased and is conducting. By exploring the electrical properties of silicon, it is possible to acquire an understanding of the inner workings of the pn junction. This page of application notes section covers pn junction diode applications. A pn junction diode is made by forming a ptype region of. If both pside and nside of the diode are lightly doped, depletion region at the junction widens.
The forward and reverse characteristics of the given pn junction diode is drawn. Construction and working of pn junction diode youtube. The circuit arrangement of the curve is shown in the figure below. Students learn the different types of biasing in diodes. Consider a diode rectifier rated for v reverse bias. Diode characteristics 2012 diodes when a semiconductor is doped so that it contains a ptype region and an ntype region, a pn junction forms at the boundary between them. 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. Since a junction forms between a p type and n type material it is called as pn junction.
The electrostatic analysis of a pn diode is of interest since it provides knowledge about the charge density and the electric field in the depletion region. It is acting as normal diode while forward biasing. A pn junction is a boundary or interface between two types of semiconductor materials, ptype and ntype, inside a single crystal of semiconductor. Students learn the different terms associated with pn junction diodes. P type and n type semiconductors, takenseparately are of very limited use. With proper biasing, pn diode allows current to flow in single direction. However, unlike a resistor, a diode does not behave linearly with respect to the applied voltage as the diode has an exponential currentvoltage iv relationship. The forward characteristics of a zener diode is shown in figure. Diodes and diode circuits tlt8016 basic analog circuits 20052006 2 3. Why does the pn junction diode exhibit current rec tification. A pn junction is the metallurgical boundary between the n and pregions of a semiconductor crystal. Working of pn junction diode with biasing, characteristics.
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. 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. Is there any relationship between the hole concentration on the pside ppo with thehole concentration on the nside. In pn junction diode, potential barrier is approximately 0. Pn junction diode applications pn diode applications. The direction of arrow is the direction of conventional current flow under forward bias. Pn junction diodes are made of two p and n semiconductor layers, permitting current to flow in only in one direction, thus being used as rectifiers. A pn junction diode is a semiconductor device with two opposite region such as ptype region and ntype region. Image source forward biasing a pn junction diode is very simple. This pn diode applications are very useful for beginners. The pn junction is the fundamental building block of the electronic age. A zener diode when reverse biased can either undergo avalanche break down or zener break down.
Pn junction diode characteristics let us consider a pn junction with a donor concentration n d and acceptor concentration n a. The objective of this experiment is to measure the iv curve for pn junction diode and to understand the characteristics of pn junction. Recitation 14 iv characteristics of pn junction diode i 6. Photodetectors pn junction can detect light when reverse biased ptype ntype when the light illuminates the pn junction, the photons energy releases free electrons and holes. It has a particular voltage known as break down voltage, at which the diode break downs while reverse biased. Basic electronics notes on vi characteristics of zener. 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. Such junctions show a pronounced rectifying behavior. The width of depletion region alters with the external applied potential. This is the basic construction of the pn junction diode.
Direction of hole flow direction of conventional current c. The pn junction is the root for semiconductor diodes. The arrow direction in the diode symbol indicates a. Real pn junction diode iv characteristics consider a. The contact surface between the layers of ptype and ntype semiconductor pieces plated together so as to form a pn junction is called the pn junction. 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. Now lets try applying an external voltage to the pn junction diode. Pn junction diode and characteristics of pn junction diode.
The word diode can be explained as di means two and ode is obtained from electrode. Lecture 15 the pn junction diode i iv characteristics november. Zener diode is a pn junction diode specially designed to operate in the reverse biased mode. The pn junction is a versatile element, which can be used as a rectifier, as an amplifier and as a voltageregulator and a switch. Objective the objective of this experiment is to measure the iv curve for pn junction diode and to understand the characteristics of pn junction. For the forward characteristics of the given pn junction diode, a graph is plotted with forward voltage along x axis and forward current along y axis. They are also called pn diodes in analogy with vacuum diodes.
On the other hand, the reverse characteristics shifts downwards with the increase in. The pn junction when ptype and ntype semiconductors brought in contact with each other, we observe a drastically changed behavior and set of new properties, from the resulting device. It is almost identical to the forward characteristics of a pn junction diode. The pn junction is a versatile element, which can be used as a. Pn junction diode baising and its vi characteristics. The analysis is very similar to that of a metalsemiconductor junction. Pn junction diode, characteristics and applications 2020. The forward current shows a sudden increase at certain forward voltage, which is known as the knee voltage.
Ppt pn junction diode powerpoint presentation free to. In the case of normal diodes the diode damages at the break down voltage. Defect analysis in semiconductor materials based on pn junction diode characteristics article pdf available in defect and diffusion forum 261262. Difference between pn junction diode and zener diode. The polarity shown, attracts electrons to the left and holes to the right. Students understand the concept of diode characteristics. As shown in the figure, pn junction diode is a 2 terminal polarity sensitive device. Students understand pn junction diodes and their working. Uniti diode current equation vi characteristics of pn junction. We also explained how depletion region is created, what barrier potential is and what diffusion. Lecture 11 pn junction diodes doolittle georgia tech. Pdf defect analysis in semiconductor materials based on. The barrier increase reduces the majority carrier diffusion to a negligible level.
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. These materials are ntype, having electrons are majority carrier and ptype material, having holes are majority carrier. It is also required to obtain the capacitancevoltage characteristics of the diode. However, unlike a resistor, a diode does not behave linearly with respect to the applied voltage as the diode has an exponential currentvoltage iv relationship and therefore we can not described its operation by simply using an equation such as ohms law. Why does the junction current in forward bias increase. It is the most essential and the basic building block of the electronic device. This allows electrical current to pass through the junction only in. Pn junction diode characteristics explained in detail. A free powerpoint ppt presentation displayed as a flash slide show on id.
They are referred to as photoelectrons and photoholes the applied voltage separates the photocarriers attracting electrons toward. It may be noted that the forward characteristics shifts upwards with increase in temperature. Let us also assume that all the donor atoms have donated free electrons and become positive donor ions and all the acceptor atoms have accepted electrons and created corresponding holes and become negative acceptor ions. Diode characteristics physics astronomy project topics. Vi characteristics of pn junction diode in 3biasing modes. The pregion is called as the anode and is connected to a positive terminal of a battery and it has holes in majority carrier and electrons in minority carrier. The other differences between the pn junction and zener diode are shown in the comparison chart. The leakage current is higher than a pn junction diode. Pn junction diode plays a vital role in our electronic fields, because of their unique property current flows in only one direction they are used in many electronic or electrical circuits like rectifiers, switches, clippers, clampers, voltage multipliers in this article, we will learn about what is a pn junction diode and how it works and also effect on pn junction diode with different.
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. The junction of n and p semiconductors is free of charge carriers. Voltampere characteristic of a pn junction diode the voltampere characteristic of the pn junction diode is a curve between the voltage over the junction and the circuit current. Pn junction diode and diode characteristics electronicstutorials. A zener diode when forward biased behaves like an ordinary pn junction diode.
However, unlike a resistor, a diode does not behave linearly with respect to the applied voltage as the diode has an exponential currentvoltage iv relationship and therefore we can not described its operation by simply using an equation such as. 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 schottky diode has a relatively low forward voltage drop and reverse recovery losses. 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 pn junction diode is one of the simplest semiconductor devices around, and which has the characteristic of passing current in only one direction only. In this physics video in hindi we explained the working of a pn junction diode for class 12. Diode current equation vi characteristics of pn junction diodeapplication half wave rectifier and full wave rectifiers with and without filters derivation of ripple. The circuit arrangement shows that the resistor is connected in series with the pn junction diode to limit the forward bias current from rising within. The effect of increased temperature on the characteristics curve of a pn junction diode is as shown in above figure. 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. Pn junction diode is a two terminal device, the characteristics of diode depends on the polarity of the external potential applied to the pn junction diode. There are plenty of electrons in the ntype material and plenty of holes in the ptype material.