Jan 21, 2019 vi characteristics of pn junction diode. By exploring the electrical properties of silicon, it is possible to acquire an understanding of the inner workings of the p n junction. Definition ptype semiconductor is suitably joined to ntype semiconductor,to conduct surface is called pn junction. A pn junction with open terminals excluding minority carriers f. This is also the case of a solar cell, where a subcircuit facilitates the task of connecting several solar cells in series or in parallel. The contact surface between the layers of ptype and n type semiconductor pieces plated together so as to form a p n junction is called the p n junction. A pn junction diode is formed with a n type semiconductor and a p type semiconductor and the doping level is normal or moderatethat is the fermi of p type will lie close to the valence band and the fermi of n type will lie c. Effects of the energygap shrinkage, the highlow junction builtin voltage, the highlevel injection, and the minoritycarrier life time on the forwardbiased currentvoltage characteristics are included. It is the most essential and the basic building block of the electronic device. Difference between pn junction diode and zener diode. What is the difference between pn junction diode and tunnel. Normal diodes will also break down with a reverse voltage but the voltage and sharpness of the knee are not as well defined as for a zener 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. The doping level of the zener diode is somewhat higher than the normal pn junction diode so that it can provide a sharp breakdown voltage. 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. Imax and imelt specify the pn junction explosion current expli which is used in the following equations. 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. 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 n side of the pn junction diode. Parameter value is scaled with area specified with the diode device. These are the easiest and basic diodes available in and use pn junction characteristics like depletion layer, diffusion and drift current. As shown in the figure, pn junction diode is a 2 terminal polarity sensitive device. 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. P n junction diode in the reversebiased configuration is sensitive to light from a range between 400nm to nm, which includes visible light.
The other differences between the pn junction and zener diode are explained below in the comparison chart. The horizontal line in the below figure represents the amount of voltage applied across the pn junction diode whereas the vertical line represents the amount of current flows in the pn junction diode. Configure an oscilloscope in xy mode to display the vi characteristics of a diode curve tracer. Forming a pn junction doping one side of a piece of silicon with boron a ptype dopant and the other side with phosphorus an ntype dopant forms a pn junction. Pn junction diode applications pn diode applications. Zener diode is a reversebiased heavilydoped pn junction diode which operates in the breakdown region. 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 n regions. This time consists of a transient and an interval of time before the diode attains a steady state. The general from of the current voltage ccs of a diode is shown in figure l. Jan 29, 2019 pn junction diode is one of the fundamental elements in electronics. Pn junction diode is one of the fundamental elements in electronics. Characteristics of junction diodes technical articles. The forwardbias and the reversebias properties of the pn junction imply. For the analysis of the accumulated data we shall use a spreadsheet.
Voltampere vi characteristics of a pn junction or semiconductor diode is the curve between voltage across the junction and the current through the circuit. Also normal diodes are not designed to operate in the breakdown region, but zener diodes can reliably operate in this region. The major difference between pn junction and the zener diode is that the pn junction diode allows current to pass only in the forward direction, whereas the zener diode allows the current to flow both in the forward and the reversed direction. In forward bias condition, current is constant until certain voltage is reached. Image source forward biasing a pn junction diode is very simple. When one side of an intrinsic semiconductor is doped with acceptor i. Basic electronics notes on vi characteristics of zener diode. The vi characteristics or voltagecurrent characteristics of the p n junction diode is shown in the below figure. Vi characteristics of pn junction diode electronics post. Silicon a single silicon atom consists of fourteen negatively. Most of the commercial leds are realized using a highly doped n and a p junction. 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. 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. The vi characteristics or voltagecurrent characteristics of the pn junction diode is shown in the below figure.
Modeling electrical characteristics of a pnjunction. Octavian florescu 2 the pn junction diode schematic diagram ptype ntype id. An ammeter is connected in series and voltmeter in parallel, while the supply is controlled through a variable resistor. If model parameter allowscaling is set to yes, the diode geometry parameters periph, width, and length are multiplied by scale, while area is multiplied by scale scale for level 11 only. To study the characteristics of the forward and reverse biased junction diodes. Abrupt depletion layer approximation let apply bias and calculate current through the pn junction currents in pn junction from sze, 1981. However, at ordinary room temperature, a potential difference of about 0. Diode is a twoterminal electronic component that conducts electric current in only one direction. The region on the left is ptype with an acceptor density na, while the region on the right is ntype with a donor density nd. The credit of discovery of the p n junction goes to american physicist russel ohi of bell laboratories. Junction diodes questions and answers electronics post. P type and n type semiconductors, takenseparately are of very limited use. Basic semiconductor physics, diodes, the nonlinear diode model, load line analysis, large signal diode models, offset diode model, transistors, large signal bjt model, load line analysis, small signal model and transistor amplification.
It is seen that the forward current rises exponentially with the applied forward voltage. Thus the load voltage remains at constant by altering the current flow through the zener diode. Simulation using multisim of pn junction diode characteristics. P n junction diode is the most fundamental and the simplest electronics device. Conduct the experiment for obtaining the forward bias vi characteristics of the given diode.
Because of its electrical properties, silicon is called a semiconductor. Working of pn junction diode with biasing, characteristics. 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. Power diodes are made of silicon pn junction with two terminals, anode and cathode. Diode is forward biased when anode is made positive with respect to the cathode. A pn junction is a boundary or interface between two types of semiconductor materials, ptype.
A pn junction diode is a twoterminal electronics element, which can be classified as either step graded or linear graded. When carriers are injected across a forwardbiased junction, it emits incoherent light. The pn junction diode is the basic semiconductor diode format. A pn junction consists of two semiconductor regions with opposite doping type as shown in figure. This is the voltage across the diode at which it starts conducting. Diode spice model dc equivalent circuit used for spice. It is also called as esaki diode named after leo esaki, who in 1973 received the nobel prize in physics for discovering the electron tunneling effect used in these diodes. Mar 27, 2019 junction diodes questions and answers q1. There are two operating regions and three possible biasing conditions for the standard junction diode and these are. 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. Pn junction diode and diode characteristics electronicstutorials. No generationrecombination in the depletion layer 6. The constant vz developed across the diode can then be applied to a load.
Pn junction diode v i characteristics of pn junction diode. A practical circuit arrangement for a pn junction diode is as shown in the following figure. May 12, 2017 this video explains about the pn junction forward bias characteristics. Here we show a graphene pn junction diode can be made exclusively from carbon. A pn junction diode is a twoterminal electronics element, which can be classified as either. Pn junction diode vi characteristics using multisim youtube. The pn junction supports unidirectional current flow. Mar 23, 2018 simulation using multisim of pn junction diode characteristics. Electrostatic analysis of a p n diode pn juntion diode. Pn junction diode explained forward bias and reverse bias. Measurements of temperature and voltage will be done using a thermocouple and an ad converter respectively. The diode conducts when forward bias is applied and it will introduce zero resistance in the circuit. This page of application notes section covers pn junction diode applications. Determine exponential diode model parameters is and n from voltage and current data.
Zero bias no external voltage potential is applied to the pn junction diode. In this article, we will focus on the iv characteristics of the junction diode, specifically the pn junction. Diode spice model ideality factor accounts for generationrecombination in the depletion region of the diode ignored in our derivation for id usual range for n is 0. A key difference is that a p n diode contains two depletion regions of opposite type. Lab 2 pn junction diode characteristic prelab objective. Vi characteristics of pn junction diode in 3biasing modes.
It means that a zener diode can be used as an alternate current path. P n junction is also a fundamental building block of many other semiconductor electronic devices such as transistors, solar cells, light emitting diodes, and integrated circuits. A typical vi characteristic for a forward biased pn junction is shown in the figure below. A pn junction is formed by joining ptype and ntype semiconductors together in very close contact. Note that the minority carrier concentration is an exponential function of the applied bias on the junction. This pn junction can be used to operate and implement the functions of a diode because it can conduct considerable current in the forward direction and roughly no current in the reverse direction. May 20, 2016 this pn junction can be used to operate and implement the functions of a diode because it can conduct considerable current in the forward direction and roughly no current in the reverse direction. Experimently find out whether the given diode is made of germanium or silicon. Diodes and transistors pdf 28p this note covers the following topics. We prefer to read our article on pn junction first before reading this guide for maximum. Same for holes these results can be reexpressed in a simpler form these two equations are known as the law of the junction. Value varies with temperature based on model tnom and device temp.
This allows electrical current to pass through the junction only. The reverse breakdown of a pn junction may occur either due to zener effect or avalanche effect. The vi characteristics of a zener diode can be divided into two parts i forward characteristics. A perfect diode is a device that only allows current to flow through it in one direction, i.
Pn junction diode and characteristics of pn junction diode. Normally the voltage is taken along the xaxis and current along yaxis. The term junction refers to the boundary interface where the two regions of the semiconductor meet. Note to those familiar with a diode turn on voltage. In case of zener diodes, the concentrations of the impurities in the semiconductors must be precisely determined typically significantly higher than in pn diodes in order to obtain the desired breakdown voltage. The dopants are assumed to be shallow, so that the electron hole density in the ntype ptype region is. 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. 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.
Therefore, like a vacuum diode, a semiconductor diode can also accomplish the. At the point of the junction, which we call the metallurgical junction, is where n d n a 0. Basic electronics notes on vi characteristics of zener. Further, customers must fully indemnify diodes incorporated and its. Pnjunction diode characteristics ppt documentation. Jan, 2015 pn junction diode characteristics lab expriment 1. Tunnel diode is a highly doped semiconductor device and is used mainly for low voltage high frequency switching applications. This p n diode applications are very useful for beginners. Modeling electrical characteristics of a pn junction silicon solar cell using pspice 5. Zener effect dominates at reverse voltages less than 5 volt whereas avalanche effect dominates above 5 v.
A light emitting diode led is essentially a pn junction diode. A pn junction is a boundary or interface between two types of semiconductor materials, ptype and ntype, inside a single crystal of semiconductor. It is used in the construction of transistors, fet, gates and many other types of integrated circuits. A pn junction diode is formed when a ptype semiconductor is fused to an n type 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.
One way to handle a pspice circuit is to define subcir cuits for the main blocks. Construction of pn junction diode and zener diode pn junction diode consists of two semiconductor layers p type anode and n type cathode. It is also required to obtain the capacitancevoltage characteristics of the diode. 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 n type material. Generating an epub file may take a long time, please be patient. A pn junction is formed by diffusing a ptype material to an n type wafer and there are several other ways as well, see your text.
Investigation of a barrier layer by the thermoprobe method pdf. A special type of pn junction diode that operates in reverse biased condition, more specifically in breakdown region is known as zener diode. Soft recovery and fast recovery where, the softness factor, sf is the ratio of t 2t 3. Pn junction diode baising and its vi characteristics. Pn junction diode junction diode symbol and static iv characteristics. A pn junction diode allows electric charges to flow in one direction, but not in. 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. Measure and plot the vi terminal characteristics of pn junction diodes.
Tunnel diode working principle and characteristics ece. When the diode is forwardbiased, it can be used in led lighting applications. 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. The horizontal line in the below figure represents the amount of voltage applied across the p n junction diode whereas the vertical line represents the amount of current flows in the p n junction diode. The diode has two terminals called a cathode and an anode. In this video, the pn junction diode has been explained. 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. 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. Pn junction diode characteristics electronic circuits and. The p n junction is the fundamental building block of the electronic age. And the working of this pn junction diode under forward and reverse bias has been. The following task will acquaints us with the characteristics of a nonlinear devise the diode.