how does p-type doping in a semiconductor work?
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Metals conduct because they have free electrons, free in the sense free from the bonding to the atom.\n\nSemi conductors do not have free electrons. They are insulators near absolute temperature. But when temperature is raised some of the electrons are freed and become conductors. \n\nAdding (doping) trivalent (three valence electrons) atoms produce P type semi conductors.\n\n By this addition we have not made any free electrons. Thus still the semiconductor can free electrons only when temperature is raised.\n\nBut since the doped atom has only three electrons, the semiconductor’s bonds are complete only when one more electron is added to every doped atom.\n\nThus the P type semiconductor is always in need of one electron per impurity atom.\n\nWe say that a ‘hole’ is there to accept an electron. The number of holes is equal to the number of trivalent atom added. \n\nThese holes are free to move from atom to atom like electrons in metals.\n\nHence P type semi conductor conducts current by the movement of holes.
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Short for complementary metal oxide semiconductor. Pronounced see-moss, CMOS is a widely used type of semiconductor. CMOS semiconductors use both NMOS (negative polarity) and PMOS (positive polarity) circuits. Since only one of the circuit types is on at any given time, CMOS chips require less power than chips using just one type of transistor. This makes them particularly attractive for use in battery-powered devices, such as portable computers. Personal computers also contain a small amount of battery-powered CMOS memory to hold the date, time, and system setup parameters.\n\nYes
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hi there. may be I can help you a little bit. I am taking a class about III-V compound right now. so what I got is this technology is good as optoelectronic. where in elemental devices such as Sillicon is not that good, therefore usually we use III-V compund such as GaAs as laser diode or something that has connection with light emitting or light receiver. but this explanation is still too general. I think if I am not misunderstood that it has better reception for photon is because the EL2 (electrical Level2) deep level which is relatively very sensitive to light. hope this is help you a little bit.
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What type of resistance--thermal, electral, or what?\n\nBoth are generally determined by the bandwidth of free electrons if any are present.  In electrical, it can also deal with impurities in the material.  In thermal, it can have to do with the irregularity of the molecular structure, the density of the solid, and the heat capacity of the molecules.
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Conductors and insulators are only building materials that provide the means for directing data from one point to another. The functionality of manipulating data comes from the special properties of semiconductors, which can be made to amplify a signal (i.e., a variation in voltage). \nWhen connected together, two very simple amplifiers (possibly as simple as one transistor each) can make a bistable circuit, one which always has one transistor conducting and the other cut off. These bistable circuits, called flipflops, can store one binary digit (bit) of information: one state, with transistor A on and B off, is considered "0" and the opposite state is "1". So a single flipflop can take the role of one bit of memory. A flipflop can be triggered to go from one state to another. When connected so one flipflop's change of state in one direction (say from 1 to 0) triggers a change (from 0 to 1 or from 1 to 0) in the next flipflop, you have the beginning of a binary counter. Similarly, flipflops in other connections can form arithmetic registers, in which two binary numbers can be compared, added, and otherise manipulated. Building on these simple forms, complex logical and arithmetic functions can be implemented.\nThe above only describes digital circuits. Semiconductor amplifiers are also used in analog and hybrid (part digital, part analog) microcircuits.
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Semiconductors have different uses:\n1. an N-P junction diode can be used as a rectifier, ie, to convert AC to DC [partly or fully] using the tranmission capabilities of transmission in forward & reverse biased situations\n2. an N-P-N or P-N-P triode can be used for rectification with amplification\n3. Doped semiconductors can also be used to construct logic gates in microelectronic devices.
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A Vaccum tube diode uses the applied voltage to create thermionic emmisions which results in sending electrons from the cathode filament to the Anode plate. This was replaced by a Semiconductor diode, which  depends on the applied electric voltage to break the barrier formed at the p-n junction. \n\nA triode is similar to a Vaccum tube diode, but gets a helping hand by concentrating the electrons using a Grid. This allows a small change to the Grid voltage to vastly increase the flow of electrons between Cathode and Anode, thus allowing Amplification.\n\nTriode Tubes were later replaced by a Semiconductor Transistors, Field effect Transistors and Bipolar Junction Transistors. However, even today, Tubes can work at far more higher voltage ranges than a semiconductor device.
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Light Emitting Diodes and How They Work.\n\nhttp://electronics.howstuffworks.com/led.htm
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A LED is a special type of semiconductor diode. Like a normal diode, it consists of a chip of semiconducting material impregnated, or doped, with impurities to create a structure called a p-n junction. As in other diodes, current flows easily from the p-side, or anode to the n-side, or cathode, but not in the reverse direction. Charge-carriers - electrons and holes flow into the junction from electrodes with different voltages. When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon as it does so.\n\nThe photon is the quantum of the electromagnetic field, for instance light.Photons are commonly the visible light.\n\nThe wavelength of the light emitted, and therefore its color, depends on the bandgap energy of the materials forming the p-n junction.
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Ultra pure silicon.  Various substances are added in minute amounts at strategic locations to change the local electrical property, creating transistors.
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The germanium diode have a forward voltage of .3 volts compared to the silicon diode with a forward voltage of .7 voltage.
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Bi CMOS just refers to a process with both CMOS and bipolars (BJT's). First, CMOS is a process that takes a substrate (let's assume p-doping, which means equivalently that there is an excess of holes or lack of electrons). They then make a few implants to form a N-MOS device. They put down two n+ areas, called the source and drain spaced apart. They then add a gate oxide (the O in MOS) and add a metal on top.\nThis isn't exactly how they make it. Most processes now are self-aligned. What's done there is to put the gate oxide down everywhere first. Then, the oxide over source and drain areas are etched away. Next, the metal (usually postilion these days) is put over the oxide. Everything is bombarded with n+ ions, forming both the poly-silicon conductor and the source and drain areas.\nSimilar things happen for a PMOS device, except first the p- substrate is bombarded with a low density of n- ions (forming an n-well inside the substrate).\nHaving an n-mos and p-mos transistor in the same process is referred to as CMOS.\nTo form a bipolar transistor, one can re-use some of the CMOS process steps but add some others. The BJT is formed with a n- emitter, p- base, and n+ collector. In this case, the n-well (and a deep n-well) is used to from the n- emitter. Inside this, a second p-well is formed to make the p- base. On top of this, n+ ions are bombarded to form the n+ collector. This forms an n-p-n bipolar transistor.
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The transistor is a solid state semiconductor device that can be used for amplification, switching, voltage stabilization, signal modulation and many other functions. It allows a variable current, from an external source, to flow between two of its terminals depending on the smaller voltage or current applied to a third terminal. Transistors are made either as separate components or as part of an integrated circuit.\n\nA semiconductor is a material with an electrical conductivity that is intermediate between that of an insulator and a conductor.\n\nThe p-n junction diode is a device made from a p-n junction. At the junction of a p-type and an n-type semiconductor there forms a region called the depletion zone which blocks current conduction from the n-type region to the p-type region, but allows current to conduct from the p-type region to the n-type region. Thus when the device is forward biased, with the p-side at higher electric potential, the diode conducts current easily; but the current is very small when the diode is reverse biased.\nExposing a semiconductor to light can generate electron-hole pairs, which increases the number of free carriers and its conductivity. Diodes optimized to take advantage of this phenomenon are known as photodiodes. Compound semiconductor diodes can also be used to generate light, as in light-emitting diodes and laser diodes.
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The movement of a hole in p-type semiconductor is in fact the movement of electrons sequentially filling a valence band vacancy.\nThis means that holes tend to move at a lower speed than electrons would in the same material with the same electric field applied.\nWe measure the effective mass of the hole by applying a field to the material and seeing how fast the holes accelerate (Newton's Law)\n\nIf you look at the characteristics of complementry transistors, which are being sold as matched pairs, you will see the extra mass of the hole manifests as an inferior characteristic in the ptype carrier transistor or FET.\n\nA p-type carrier is a hole in a semiconductor.\nA positron is a hole in space that can be filled by an electron.  The hole in space has a mass, velocity and the opposite quantum numbers of the electron.\nHoles and positrons are not the same animal!!!!!!
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This is a good question.  Many of the electronic devices today use semi-conductor devices that work at low voltages.  However, that has only been the case since the mid-1960's on average.  Prior to this electronic devices used Vacuum Tubes.  These vacuum tubes used very high voltage DC to cause the flow from an cathode to an anode to flow.\n\nUntil the development of the High Voltage semi-conductor or Silicon Diode most electronics circuits used Vacuum Tube Diodes.  These Diodes would allow for current to flow in only one polarity the same as silicon diodes.\n\nAn intermediate high voltage diode between the vacuum tube diode and the silicon diode was the Selenium Diode.  This diode was the first solid state diode; however, they were not very efficient nor were very effective when high currents were required.  However, today selenium diodes are still in use where size is not an issue.  These diodes generally can work with voltages up to about 2000 VAC and currents as high as 100 amps.\n\nGenerally, most high voltage circuits today use silicon diodes with a high Peak Inverse Voltage (PIC).  On average most cost effective Silicon diodes have a PIV of 600 volts DC.  To increase the voltage that diodes can work you can put them in series, or connected one after then other.  This way you can daisy chain several diodes together to achieve a PIV of up to around (3 in a row) or 1800 volts before the capacitance could be a problem.  This same type of diode works at one amp, if you place them in parallel or side by side you can increase the amount of current your bridge can support.  Again I would not recommend using more then 3 semi-conductor or silicon diodes in parallel, or use for rectifying more 3 Amps of voltage.\n\nTo make your Neon Sign DC voltage converter I would recommend using selenium diodes specifically designed for the high voltage you are talking about.  These diodes and semi-conductor diodes are still available from a number of retail suppliers.  If you would like to try a Vacuum Tube diode, similar to the one used in the high voltage section of a Color TV, Ratheon is the only supplier I can recall that still makes vacuum tube diodes.
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this will explain it\nhttp://www.daniweb.com/techtalkforums/showpost.php?p=75196&postcount=43
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Of course. \nThe actual junction of an N type and P type is what prevents conduction when reverse biased.