In this type of diode, we dope one side of a semiconductor piece with an acceptor impurity and another side with a donor impurity. Pn junction diode and diode characteristics electronicstutorials. Semiconductor pnjunction diodes physically, diodes are formed by the interface between two regions of oppositely doped semiconductor i. We now consider a pn diode with an applied bias voltage, va. These electrons are not bound and are free to move about. Pn junction diode is integral for all electronic devices to operate, aggregating all forms of carrier transport, generation, and recombination. Such junctions show a pronounced rectifying behavior. Pn junction diode 2 diode introduction a diode is formed by joining an ntype semiconductor with a ptype semiconductor. 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. A pn junction diode is a twoterminal electronics element, which can be classified as either. The arrow indicates the flow of current through it when the diode is in forward biased mode, the dash or the block at the tip of the arrow indicates the blockage of current from the opposite direction. The simplest application of the pn junction is the bipolar junction diode often made from silicon or germanium.
Pn junction diode is one of the fundamental elements in electronics. Pn junction diodes form the basis not only of solar cells, but of many other electronic devices such as leds, lasers, photodiodes and bipolar junction transistors bjts. Pn junctions worksheet discrete semiconductor devices. Under the guidance of department of physics kendriya vidyalaya drdo c v raman nagar bengaluru560093.
A bipolar junction diode is basically a pn junction with conducting terminals attached to each side of the junction. A k schematic symbol for a pn junction diode p n representative structure for a pn junction diode zener diodes. Lecture 15 the pn junction diode i iv characteristics november 1, 2005 contents. A pn junction diode is a twoterminal electronics element, which can be classified as either step graded or linear graded.
The anode which is the positive terminal of a diode is represented with a and the cathode, which is the negative terminal is represented with k. This page of application notes section covers pn junction diode applications. A pn junction diode allows electric charges to flow in one direction, but not in the opposite direction. Pn junction diode and characteristics of pn junction diode. We have seen how a diode is made with p and n semiconductors but. Aug 01, 2016 when the ntype semiconductor and ptype semiconductor materials are first joined together a very large density gradient exists between both sides of the pn junction. Minor project report on pn junction, zener diode, led. Kendriya vidyalaya sangathan bengaluru region bengaluru submitted in partial fulfillment of the requirements for the aissce cbse board examination in physics for the academic year 20152016 to be carried out by name. A semiconductor diode is a two terminal electronic component with a pn junction. Apr 05, 2019 in this tutorial, we will learn about pn junction diodes and in particular the characteristics and working of pn junction diode.
Design a circuit that tests the forward voltage v f of a pnjunction diode, so you may measure the voltage yourself, without the use of a special diodetesting meter. A pn junction diode is a basic semiconductor device that controls the flow of electric current in a circuit. 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 is the voltage required to reach a flat band diagram and sets an upper limit typically an overestimate for the voltage that can be applied to a diode before it burns itself up. Jan 15, 2017 minor project report on pn junction, zener diode, led characteristics 1. A zener diode is a type of diode that allows current to flow in the conventional manner from its. Jan 04, 2020 a pn junction is the simplest form of the semiconductor diode. Today, im going to unlock the details on the introduction to pn junction. So, the base region actually works as the input and both the emitter and collector regions as output. Dec 27, 2017 the symbolic representation of the diode is as follows. Use the diode equation for that state to solve the circuit equations and find i d and v d 3.
They are also called pn diodes in analogy with vacuum diodes. The behaviour of the pn junction with regards to the potential barriers width produces an asymmetrical conducting two terminal device, better known as the pn junction diode. The pn junction solidstate device theory electronics. Note to those familiar with a diode turn on voltage.
One side is doped with a donor or ntype impurity which releases electrons into the semiconductor lattice. Are specifically designed to operate under reverse breakdown conditions. A pn junction is the metallurgical boundary between the n and pregions of a semiconductor crystal. With the diode check function a specific known voltage is applied from the meter across the diode. By exploring the electrical properties of silicon, it is possible to acquire an understanding of the inner workings of the pn junction. 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 is a versatile element, which can be used as a. The doping profile is our starting point to analyze pn junction electrostatics, since it combines the information given for n d and n a. A pnjunction diode is formed when a ptype semiconductor is fused to an ntype semiconductor creating a potential barrier voltage across the diode junction. Pn junction tutorial introduction to pn junction diodes. A forward bias corresponds to applying a positive voltage to the anode the ptype region relative to the cathode the ntype region.
This is a junction formed when two different types of semiconductor material i. This is a building block for the development of the diode. Semiconductor physics semiconductors and diodessemiconductors. A pnjunction diode is formed by joining together ntype and ptype silicon. Abrupt depletion layer approximation let apply bias and calculate current through the pn. Note that a pnjunction diode cannot be made by simply pushing a piece of ptype against another of ntype. Sep 10, 2016 pn junction and zener diode 12 class project. How much voltage is assumed to be dropped across a conducting silicon pn junction. Objective questions on pn junction diode electrical study. 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 name diode is derived from diode which means a device that has two electrodes. In order to simplify analysis of circuits containing pn junctions, a standard forward voltage drop is assumed for any conducting junction, the exact figure depending on the type of semiconductor material the junction is made of.
Transistor and diode studies static properties of this type of diode structure was made, and numerical computations are being completed. Minor project report on pn junction, zener diode, led characteristics 1. To study and verify the functionality of a pn junction diode in forward bias b pointcontact diode in reverse bias. A pn junction is formed by diffusing a ptype material to an ntype wafer and there are several other ways as well, see your text. This is the basic construction of the pn junction diode. This portion of an npn bjt is just like a pn junction. 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.
Coed school kolar road bhoapl department of physics project report investigatoryproject on pn junction and diodes project report submitted by govind patel submitted to mrs ratna hajela registerationno. Image source forward biasing a pn junction diode is very simple. A pn junction aggregates the recombination, generation, diffusion and drift effects described in the previous pages into a single device. Pn junction diode 1 ee105 fall 2014 microelectronic devices and circuits prof. The pn junction diode is the typical diode that has been used in the previous circuits. The symbolic representation of the diode is as follows. The result is that some of the free electrons from the donor impurity atoms begi. The boltzmann approximation is to say that the resulting current being small compared with the components of this current, we consider that we are still in quasi equilibrium and therefore that the currents equation is still valid by replacing v bi by v. Pn junctions consist of two semiconductor regions of opposite type.
It is one of the simplest semiconductor devices as. In the positive half cycle, during the time interval 0 to t2, diode d will be forward biased and conduct, i. Diode d1 protects q1 from the high voltage pulse that is generated in the relay. The diode conducts when forward bias is applied and it will introduce zero resistance in the circuit.
Ee105 fall 2014 microelectronic devices and circuits. Volume ii 2nd edition modular series on solid state dev. A report including analyses of high injection in the forward direction, large reversevoltage conditions, and the behavior of the incremental. The pn junction is the fundamental building block of the electronic age. The electrical characteristics of leds are the same as normal. 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. Pn junction underbiasing 14 boltzmanns approximation.
The recombination at the junction allows battery current to flow through the pn junction diode. To know the anode and cathode of a practical diode, a fine line is drawn on the. The emitterbase junction of a bipolar npn transistor behaves as a zener diode, with. Investigation of a barrier layer by the thermoprobe method pdf. Consequently, the i b and v be relationship in the. Testing a diode is quite simple, particularly if the multimeter used has a diode check function. Introduction to pn junction the engineering projects. Pn junction is a significant building block and it is one among the indispensable structures. The most common type of semiconductor diode is the silicon diode. This pn diode applications are very useful for beginners. 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. The forwardbias and the reversebias properties of the pn junction imply that it can be used as a diode. I believe this book will be helpful for the students for their mini project.
A pn junction is a boundary or interface between two types of semiconductor materials, ptype. Write down all circuit equations and simplify as much as possible 2. Take the pn junctions discrete semiconductor devices and circuits worksheet. This understanding will lay a better foundation for exploring further into different aspects of semiconductor electronics. As shown in the figure, pn junction diode is a 2 terminal polarity sensitive device. 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 pn junction has the very useful property that electrons are only able to flow in one direction. In this tutorial, we will learn about pn junction diodes and in particular the characteristics and working of pn junction diode. From the above, it follows that zero power dissipation occurs in an ideal diode. When the ntype semiconductor and ptype semiconductor materials are first joined together a very large density gradient exists between both sides of the pn junction. No generationrecombination in the depletion layer 6. Semiconductor pn junction diodes can be formed from materials other than silicon, such as germanium, selenium, and a host of semiconductor materials used in. Coed school kolar road bhoapl department of physics project report investigatoryproject on pn junction and diodes project report submitted by govind patel submitted to mrs ratna hajela. It is used for many forms of rectification for current levels both large and small, as well as high and low voltage levels, and it finds many uses in all manner of electronic circuits. The load resistance r l is connected to these terminals through a pn junction diode d. The diode uses the properties caused by the depletion area of the junction. Definition, symbol, and types of diodes electrical4u. The potential at terminal x with respect to y will vary as a sine function with time.
The junction diode basic operation the diode is fabricated of a semiconductor material, usually silicon, which is doped with two impurities. They are referred to as photoelectrons and photoholes the applied voltage separates the photocarriers attracting electrons toward. Pn junction diode applications pn diode applications. Silicon a single silicon atom consists of fourteen negatively. Semiconductor pn junction diodes physically, diodes are formed by the interface between two regions of oppositely doped semiconductor i. Majority carriers can diffuse across the pn junction depletion region, even though the electric field impedes their crossing. The pn junction diode is the basic semiconductor diode format. With the diode check function a good diode will show approximately. Pn junctions worksheet discrete semiconductor devices and. Objective questions on pn junction diode electrical. Pn junction diode baising and its vi characteristics.
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