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Topic: PN junction

In the News (Sun 20 Apr 14)

  What is an LED? | LED Lighting Systems | Lighting Answers | NLPIP
Junction temperature - For light emitting diodes, the temperature of the light-emitting portion of the device (see PN junction), which is inversely correlated with its light output.
PN junction - For light emitting diodes, the portion of the device where positive and negative charges combine to produce light.
When a forward voltage is applied to the semiconducting element forming the PN junction (heretofore referred to as the junction), electrons move from the N area toward the P area and holes move toward the N area.
www.lrc.rpi.edu /programs/NLPIP/lightingAnswers/led/whatIsAnLED.asp   (535 words)

 Contactless LSI junction leakage testing method - Patent 4015203
PN junction leakage in a semiconductor specimen including large scale integration specimens is measured by inductively coupling high frequency oscillations to the specimen while the specimen is subjected to pulsed light of selected intensity.
The capacitance of the junction or junctions in the sample is charged to an amount dependent on the intensity of the pulsed light.
A semiconductor PN junction may be represented by the equivalent circuit consisting of three elements connected in parallel with each other, i.e., a capacitor representing junction capacitance, a diode representing the rectification properties of the junction, and a resistor representing the leakage resistance of the junction.
www.freepatentsonline.com /4015203.html   (3344 words)

 Electronics - PN Junction   (Site not responding. Last check: 2007-10-11)
PN Junctions work with the use of 2 layers of separated semiconductor material.
A Junction is created between the two layers whereby the free electrons in the N-Type layer can pass through the junction into the P-type layer.
Because of this, a "depletion zone" is formed around the junction where the holes and electrons meet.
www.angelfire.com /electronic2/motegi/pnj.htm   (206 words)

 p-n Junction
Therefore, when a p-n junction is reverse biased, there will be no current flow because of majority carriers but a very small amount of current because of minority carriers crossing the junction.
The electrons in the n-type region near the junction are repelled by the fixed acceptor atoms in the p-type.
A p-n junction device used as a voltage-variable capacitor is known as a varactor diode.
www.mtmi.vu.lt /pfk/funkc_dariniai/diod   (2687 words)

 The P-N Junction
When a p-n junction is formed, some of the free electrons in the n-region diffuse across the junction and combine with holes to form negative ions.
When a p-n junction is formed, some of the electrons from the n-region which have reached the conduction band are free to diffuse across the junction and combine with holes.
For conduction in the device, electrons from the N region must move to the junction and combine with holes in the P region.
hyperphysics.phy-astr.gsu.edu /hbase/solids/pnjun.html   (456 words)

 Semiconductor device - Patent 4001873
A polycrystalline silicon film is disposed on the face of an N type silicon substrate including a termination of a PN junction to extend slightly beyond the termination of the PN junction from the periphery of the substrate.
In the planar diode thus formed, the PN junction 14 terminates at 22 on the upper main face of the substrate 10 to intersect that main face.
1, a PN junction 14 is formed between the P.sup.+ type region 12 and the N type substrate 10 to terminate at 22 on the main face of the substrate 10.
www.freepatentsonline.com /4001873.html   (3164 words)

 Tunnel diode - Wikipedia, the free encyclopedia
Under normal forward bias operation, as voltage begins to increase, electrons at first tunnel through the p-n junction barrier because electron states in the conduction band on the n-side become aligned with valence band hole states on the p-side of the pn junction.
Under reverse bias at sufficiently high reverse voltage, electrons flow in the opposite direction, as now different electron states on each side of the pn junction become increasingly aligned and tunnel through the pn junction barrier in reverse direction — this is the Zener effect that also occurs in zener diodes.
In a conventional semiconductor diode, conduction takes place while the PN junction is forward biased and blocks current flow when the junction is reverse biased.
en.wikipedia.org /wiki/Tunnel_diode   (570 words)

 Introduction - Junction Field-Effect Transistors - JFET
In a junction field-effect transistor, or JFET, the controlled current passes from source to drain, or from drain to source as the case may be.
This behavior is due to the depletion region of the PN junction expanding under the influence of a reverse-bias voltage, eventually occupying the entire width of the channel if the voltage is great enough.
However, the PN junction of a JFET is not built to handle any substantial current itself, and thus it is not recommended to forward-bias the junction under any circumstances.
www.opamp-electronics.com /tutorials/introduction_3_05_01.htm   (675 words)

 Radio-Electronics.Com :: Semiconductor PN Junction Diode
The semiconductor diode PN junction with reverse bias
The PN junction is not an ideal rectifier diode having infinite resistance in the reverse direction and no resistance in the forward direction.
However the PN junction is also the basis of the bipolar junction transistor, and the junction FET.
www.radio-electronics.com /info/data/semicond/pnjunction.php   (916 words)

 The PN Junction   (Site not responding. Last check: 2007-10-11)
Therefore, a practical PN junction can only be created by inserting different impurities into different parts of a single crystal.
In response, we see that the positive voltage applied to the N-type material attracts any free electrons towards the end of the crystal and away from the junction, while the negative voltage applied to the P-type end attracts holes away from the junction on this end.
The result is that all available current carriers are attracted away from the junction, and the depletion region grows correspondingly larger.
www.play-hookey.com /semiconductors/pn_junction.html   (981 words)

 PN Junction Diode
During the processing of a PN junction diode when the Ptype material and the Ntype material are joined together.
Now, as much as in a PN junction, the *electrostatic potential* is not constant, but makes the known jump in the depletion layer (where there is hence an electrostatic field), normally, the electrochemical potential is constant across the junction for both kinds of charge carriers (which is nothing else but the thermodynamic condition of equilibrium).
I also realized wich was the simple "electromagnetic" explanation to the fact that if you put a voltage meter across a PN junction diode you get 0 V. When the diode is not forward biased, the built-in potential stops the carriers in the neutral regions from diffusing and entering the depletion region.
www.physicsforums.com /showthread.php?t=124455   (2673 words)

 Lessons In Electric Circuits -- Volume III (Semiconductors) - Chapter 5
Unlike the bipolar junction transistor where the emitter is clearly distinguished from the collector by the arrowhead, a JFET's source and drain lines both run perpendicular into the bar representing the semiconductor channel.
In a junction field-effect transistor (JFET), there is a PN junction between the gate and source which is normally reverse-biased for control of source-drain current.
With less reverse-bias voltage impressed across the gate-source junction, the depletion region is not as wide as it was before, thus "opening" the channel for charge carriers and increasing the drain current figure.
www.ibiblio.org /obp/electricCircuits/Semi/SEMI_5.html   (3461 words)

 PN junction diode
For a PN junction diode, the total potential across the semiconductor equals the built-in potential minus the applied voltage.
The reason they do wander is because of the extra electrons on the N-side and Holes on the P-side due to the power source feeding the extra carriers to the respective sides and not vice versa (the Va is not feeding holes to the N-side and electrons to the P-side).
Phi is indeed the drop across the semiconductor junction, but since Vbi is going to be present regardless of the Va, Vbi doesn't play a role in the potential seen in other devices.
www.physicsforums.com /showthread.php?p=1059115#post1059115   (2883 words)

 p-n Junctions
A p-n junction consists of two semiconductor regions with opposite doping type as shown in Figure 4.2.1.
The junction is biased with a voltage V
We will call the junction forward-biased if a positive voltage is applied to the p-doped region and reversed-biased if a negative voltage is applied to the p-doped region.
ece-www.colorado.edu /~bart/book/book/chapter4/ch4_2.htm   (854 words)

 Bipolar Junction Transistors
A Bipolar Transistor essentially consists of a pair of PN Junction Diodes that are joined back-to-back.
Since the Emitter-Base junction is a PN diode we can expect to see a current when we apply forward voltages of this sort of size.
As the voltages applied to the base-emitter and base-collector junctions are changed, the depletion layer widths and the quasi-neutral regions vary as well.
www.mtmi.vu.lt /pfk/funkc_dariniai/transistor/bipolar_transistor.htm   (3554 words)

 PN Junction   (Site not responding. Last check: 2007-10-11)
At the junction some electrons from the n-type will recombine with holes in the p-type.
This causes the p-type material to become negatively charged near the junction because of the extra electrons.
Around the junction there will be a layer – called the depletion layer – in which all of the free holes and electrons will have been removed.
eserver.bell.ac.uk /d4ff/pn_junction.htm   (174 words)

 The Junction FET   (Site not responding. Last check: 2007-10-11)
However, we will also leave the pn junction in place, centered along the n-type section as showm.
Because the electric field produced by the applied gate voltage controls the resistance of the channel (and therefore the current flowing through the channel), this device is known as a field-effect transistor (FET).
In addition, because the control voltage at the gate is applied to a pn junction, and because the channel is made of n-type semiconductor material, the device is properly called an n-channel junction field-effect transistor, or n-channel JFET.
www.play-hookey.com /semiconductors/junction_fet.html   (691 words)

 pn junction-diode-pn junction diode-electronics-learn electronics-semiconductor diode
A pn - junction diode is an electronic device formed from a p-type and an n-type substance semiconductor.
Thus a junction is formed between p-type section and an n-type section of germanium.
Due to induction of these layers a potential barrier is now developed across the junction and further flow of charges is prevented from one side to the other.
www.citycollegiate.com /electronicsXc.htm   (231 words)

 Tuning VFOs without air variable capacitors   (Site not responding. Last check: 2007-10-11)
When building a PN junction tuned VFO, it is probably best to build the entire VFO, ensure that it is working and then add your tuning circuit.
In a PN-junction, the P layer of the junction is the anode and the N layer is the cathode.
The frequency range may be influenced by where and how the PN junction is connected to the tank circuit.
www.qrp.pops.net /pnj.htm   (5187 words)

 Current flow in PN Junction   (Site not responding. Last check: 2007-10-11)
At a constant forward-bias, the number of holes injected across the junction per unit time equals the number of holes lost by recombination, thus establishing a steady state (i.e., constant in time).
Electrons (blue) are injected from n-side (blue) to the p-side (red) across the junction (or depletion region, gray).
The numerical values are for a Si pn junction diode.
www.acsu.buffalo.edu /~wie/applet/students/jiawang/pn.html   (446 words)

 PN Junction Properties Calculator
The abrupt junction is one where the doping is constant on both sides of the junction and changes instantly at the junction.
A subset of the abrupt junction is the one-sided abrupt junction, which can also be calculated here.
The doping gradient is the rate of change of the doping concentration.
www.ee.byu.edu /cleanroom/pn_junction.phtml   (131 words)

 Microelectronic Devices: II. PN Diode And Bipolar Transistor   (Site not responding. Last check: 2007-10-11)
This course covers the fundamental physics underlying the operation of pn Diodes and Bipolar Transistors.
pn Diode and Bipolar Transistor describes the physics and modeling of pn diodes and bipolar transistors.
pn diode electrostatics in thermal equilibrium and under bias, junction capacitance.
www.electronics.ca /training/device_technology/co145.html   (506 words)

 Amazon.com: The PN Junction Diode, Volume II (2nd Edition): Books: George W. Neudeck   (Site not responding. Last check: 2007-10-11)
The book attempts to simplify the physics of PN junction diodes, especially by using suggestive sketches in place of mathematical reasoning.
For example in the derivation of the ideal diode equation, the author claims that both drift and diffusion currents flow from one side of the junction to the other, which when no bias is applied balance for both electrons and holes.
In fact no drift currents flow across an ideal PN junction, since no carriers exist where there is an electric field.
www.amazon.com /PN-Junction-Diode-II-2nd/dp/0201122960   (1215 words)

 NANOHUB.ORG - PN Junction Lab   (Site not responding. Last check: 2007-10-11)
PN Junction Lab - Everything you need to explore and teach the basic concepts of P-N junction devices.
It contains 7 problems which lead students through a comparison of the depletion approximation and the exact analysis of a PN junction diode.
Students compute the exact solution by using the PN Junction Lab...
www.nanohub.org /simulation_tools/pnjunction_tool_information   (327 words)

 STM Image of PN Junction   (Site not responding. Last check: 2007-10-11)
The average profiles taken across the above image (red) and a similar +2V sample bias image (fl) show a dip on each side of the stripe that is dramatically affected by tunneling polarity and thus electronic in origin.
The locations of these dips - on the n side of the metallurgical junction - suggest that they are associated with the depletion zone.
They are the grooves that were also seen in AFM and are roughly at the metallurgical junctions.
members.cruzio.com /~hildner/page2.htm   (123 words)

 The PN Junction and the Diode Effect   (Site not responding. Last check: 2007-10-11)
The concentration of positive and negative carriers are quite different on opposite sides of the junction and the thermal energy-powered diffusion of positive carriers into the N-type material and negative carriers into the P-type material occurs.
The N-type material acquires an excess of positive charge near the junction and the P-type material acquires an excess of negative charge.
To complete the diode conductor, leads are placed at the ends of the PN junction.
www.phys.ualberta.ca /~gingrich/phys395/notes/node57.html   (139 words)

 Junction FET   (Site not responding. Last check: 2007-10-11)
The small signal Y-parameter matrix of the intrinsic junction FET writes as follows.
The junction capacitances are modeled with the following equations.
In addition, saturation current, gate-junction potential and zero-bias junction capacitances have built-in temperature dependence.
qucs.sourceforge.net /tech/node44.html   (339 words)

 PN Junction operation
Now that you are familiar with P- and N-type materials, how these materials are joined together to form a diode, and the function of the diode, let us continue our discussion with the operation of the PN junction.
But before we can understand how the PN junction works, we must first consider current flow in the materials that make up the junction and what happens initially within the junction when these two materials are joined together.
Conduction in the N-type semiconductor, or crystal, is similar to conduction in a copper wire.
www.tpub.com /neets/book7/24g.htm   (384 words)

 Formation of pn junction and its band diagram   (Site not responding. Last check: 2007-10-11)
A click on a button will show an animated formation of PN junction diode, a snapshot of which is:
Initiate the pn junction formation by clicking the 'FormJunction' button or using mouse drag and watch the physical system approach a new (electro-thermal) equilibrium which is characterized by a constant Fermi level throughout the material.
The white region between the red (p-type) and blue (n-type) regions is the transition (or depletion) region where most of the free carriers are depleted.
www.acsu.buffalo.edu /~wie/applet/pnformation/pnformation.html   (207 words)

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