They are also called pn diodes in analogy with vacuum diodes. Pn junction diode experiment using breadboard and simple components duration. Simulator procedure as performed through the online labs select the characteristics of diode from the. Electrons and holes diffuse from areas of high concentration toward areas of low concentration. To study and verify the functionality of a pn junction diode in forward bias b pointcontact diode in reverse lab report 1. A suitable positive voltage forward bias applied between the two ends of the pn junction can supply the free electrons and holes with the extra energy. Experiment 16 the pn junction introduction in this experiment on the physics of the pn junction, a determination is made of both the universal constant ek i. Conduct the experiment for obtaining the forward bias vi characteristics of the given diode. 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. In actual practice, the pn junction is not formed just by bringing a ptype semiconductor block near to an ntype semiconductor block. The most common method of making p n junction is called alloying. Analytically, this occurs when the gatetodrain voltage v. In the reverse bias, the saturated value of the reverse current for a pn junction diode is given by, is constant.
It consist of two regions of homogeneous semiconductor, one doped with acceptors ptype and the other one doped with donors ntype. The objective of this experiment is to measure the iv curve for pn junction diode and to understand the characteristics of pn junction. If you find these terms foreign, just read the chapter about. What are the advantages and disadvantages of pn junction. In forward bias condition, current is constant until certain voltage is reached. Pdf experiment on the physics of pn junction giacomo. A pn junction formed by the doping f ptype and ntype material on a single crystal. Forward bias operation the pn junction supports unidirectional current flow. Zener diode is a pn junction diode specially designed to operate in. The pn junction is the root for semiconductor diodes. Diodes are mostly used in practice for emitting light as light emitting diodes, leds or controlling voltages in various circuits. It is a basic semiconductor device that allows the flow of current in a unified direction.
Experiment 16 the pn junction university college dublin. Iv characteristics pn junction diode reverse biasing a pn junction when the polarity of the battery is reversed, the cathode is connected to positive end of the battery and anode to negative. Zener diode, resistors, power supply, multi meter circuit diagram. 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. Practical report on diode characteristics pdf scoop.
The operation of the jfet is based on controlling the bias on the pn junction between gate and channel note that a single pn junction is discussed since. Increase the current in small steps and note down the corresponding junction voltage. It is the most essential and the basic building block of the electronic device. A junction diode is very useful serving as a rectifier, a switch, or a voltage reference, in an electronic circuit. Some of the voltage and current division lab report. The graph shows the reverse vi characteristics of the given pn junction diode.
Pn junctions consist of two semiconductor regions of opposite type. Diode pn junction when p and n type silicon are brought together during manufacture, a junction is created where the p type and n type materials meet, and holes close to the junction in the p type silicon are attracted into negatively charged n type material at the other side of the junction. The forward bias characteristic of zener diode is same as the normal pn junction diode but in reverse bias it has different characteristic. Due to this characteristic, the diode finds number of applications as given below. Pn junction diode vi characteristics in forward and. The conversion of alternating current into direct current is known as rectification. The pn junction forms the basis of the semiconductor diode. Such junctions show a pronounced rectifying behavior. Due to heavily doped, its depletion layer is very thin and is order of micrometer. Experimently find out whether the given diode is made of germanium or silicon. This simulation will give you an idea of the voltage and current values to be measured in the lab.
An undoped semiconductor is called an intrinsic semiconductor. A pn junction diode is formed when a single crystal of semiconductor is doped with acceptors impurities pentavalent on one side and donor impurities trivalent on the other side. 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. To analyse the dependence of the builtin potential or barrier voltage vo with the dopant concentration na and nd of the p and nregions, respectively. Introduction to semiconductors and the pn junction diode. It is the reverse biased havily doped silicon or germanium pn junction diode which is operated in the breakdown region where current is limited by both external resistance and power dissipation of the diode. 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. Simulate in pspice the iv characteristic for d1n4002 pn junction rectifier diode. Creating a pn junction doping doping is the replacement of a small number of atoms in the lattice by atoms of neighboring columns from the periodic table these doping atoms create energy levels within the band gap and therefore alter the conductivity.
A pn junction diode allows electric current when it is forward biased and blocks electric current when it is reverse biased. To find cutin voltage for silicon pn junction diode. However, in real experiment in the lab this circuit. Experiment on the physics of the pn junction article pdf available in american journal of physics 621. Pn junction diode and its characteristics in chapter 1 understanding the pn junction, we have seen how a pn junction is formed from a ptype and ntype semiconductor. To plot voltampere characteristics of silicon pn junction diode. Vi characteristics of pn junction diode in 3biasing modes. If the transition region between the two semiconductor types is assumed to be thin the junction is said to be abrupt or step applications. Thus, electrons diffuse from the nregion to the pregion.
Definition ptype semiconductor is suitably joined to ntype semiconductor,to conduct surface is called pn junction. Introduction to semiconductors and the pn junction diode robert clancy 04329741 april 10, 2006 abstract in this experiment the iv characteristicof the pn junction diode is determined andthe applicationofthe diodeasarecti. 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. Introduction a simple experiment on the physics of the pn junction may be carried out in undergraduate laboratory courses, providing a determination of both the universal constant ek i.
Connect the diode to the pn junction setup as shown in the figure 1. This causes electrons from nregion to get attracted to positive terminal of the battery and holes by the negative terminal. Alan doolittle 2 2 ln ln ln i a d bi a i d p n bi n n n q kt v n n n q kt n x n x q kt v movement of electrons and holes when forming the junction for nand1015cm3 in silicon at room temperature, vbi0. P type and n type semiconductors, takenseparately are of very limited use. Calculate lniand plot a graph between lniand junction voltage, v. Junction field effect transistor jfet the single channel junction fieldeffect transistor jfet. At threshold therefore, the sum of the gate and substrate junction nside depletions approximates the nchannel thickness t c. These experiments have been submitted by third parties and agilent has not tested any of the experiments. The basic device formed from this pn junction is of two terminals. Plot a graph with reverse voltage along x axis and reverse current along y axis. A pn junction is the metallurgical boundary between the n and pregions of a semiconductor crystal.
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