Semiconductor Definition and 400 Threads

Hi, I am looking for a good book or any other online resource on semiconductor physics. What I need the book to cover is: The PN junction i.e. the diode BJT transistors MOSFETS In particullar I am interested in the derivation of the equations of the above components, the Shockley...

hey guys i just wanted to confirm something; so, for systems of continuous energy states (or small separations of discrete energy states), we can plot a graph like this and call the fermi energy the middle point where Probability=1/2. like this where, if T=0K, the transition from...

I understood that the fermi level is a hypothetical energy level given by the Fermi-Dirac distribution where the probability of finding an electron is exactly 50%. My question is: it always takes (Ec-Ev) energy to excite the electrons in the conduction band in an intrinsic semiconductor or...

Attached is a picture of three different electron configurations in a semiconductor. It seems from the author of my book that it should be obvious that the middle one has a lot lower conductivity than the 2 other. Why is that? I mean it is possible for the electrons to move in the conduction...

In my college, we used this transistor named SL100 and another one named CL100 for various experiments. But why are they named that way? I browsed the net for an answer for almost an hour but couldn't find a proper answer to this? What does S and L mean? what does 100 mean? From the Datasheets...

Homework Statement The lab is attached. I've also attached the pre-lab just for the diagram. Homework Equations The Attempt at a Solution Can anyone think of some good errors for this lab? We ended up with ~80% error. I've thought of two: 1. Adjusting the potentiometer so...

How do the effects of semiconductor semiconductor doping affect the Hall effect? For instance, consider number 4 and 5 in the following sample: Using the right hand rule, B points downwards, conventional current points to the right (because of the 5V battery), and therefore, the force...

Hi, Iam having a hard time understanding the benefits of using a semiconductor to construct e.g. a photodiode that creates a current in proportion of the energy deposited by radiation. Text books says that semiconductor is preferred as detectors due to high density (larger chance for...

Hi, Iam reading the book Glen F. Knoll Radiation Detection and Measurements, and Iam having a trouble understanding a certain part of the chapter about semiconductor, he writes: Electron-hole pairs that are created within the depletion region by the passage of radiation will be swept out...

Main reason why semiconductor is used and not a "pure" metal for detec Hi, I have question regarding why semiconductor is preferred in the field of radiation detection. I have read that they can be doped and their conductivity can be manipulated, but I can't see why this is not possible...

Homework Statement Explain why a pure semiconductor crystal will always have equal numbers of electrons and holes present as electrical carriers. Explain why a crystal with additional donor impurities will norally have more electrons in the conduction band than holes in the valence band, still...

Homework Statement P-type silicon can be doped in the range from 5x1014 cm-3 to 1020 cm-3. Determine the maximum possible number of minority electrons in a neutral P-type region if the device area is limited to AD = 1 cm x 1 cm and the thickness of the P-type region is limited to tP=100 μm...

I do not know if this question relates to this division and would appreciate if it would be moved to proper division. I want to buy a piece of fine, pure, highly doped semiconductor with dimensions approximately: 7 cm X 7 cm X 1 cm (2 in. X 2 in. X 1/2 in.) It supposed to be just fine and...

Hi, I was wondering if someone could tell me what the best way would be to determine if a semiconductor laser is broken using a multimeter? I have a semiconductgor laser that is still emitting but the signal appears lower than expected and it is hard to tell if it is broken internally...

What exactly is a concentration of acceptor in p-type semiconductor? The symbol is Na. Lets say there's a Silicone, and it has 3 valence electrons, when it receives electrons (releases hole), it becomes negatively ionized, right? So that should mean Silicone is an acceptor, right? But what is...

Homework Statement "Use the equation I=nAve to justify why charges travel faster in semiconductor than in metallic conductor. Assume that the dimensions and current are the same. " Homework Equations I=nAve I know I = current, n = number density, A= cross sectional area v= drift...

This is a question about the band gap. In a semiconductor, the chemical potential is in between the valence and conduction bands, so that the valence band is full and the conduction band is empty at T＝0. What happens if you try to add another electron to the system? It seems that it wouldn't...

In p-type semiconductor the charge carriers are said to be positive, that is electron hole. But still isn't the electrons are movoing ? If positives move to the right that means that in reality electrons are moving to the left. Then how is it that the hall effect experiment for p-type...

For intrinsic semiconductor, the know its conductivity=2 neμ , where his the number of electron per cubic meter, e is the charge of an electron, μ is the electron mobility. But if I want to calculate the conductivity of a conductor= neμ. Why not consider the hole in? Electron leaves its...

Hi, I am planning to join M.S in MIS/IS next year. For e.g:-i)http://mays.tamu.edu/info/prospective/undergraduate/mis/ ii)http://business.uc.edu/programs/graduate/ms-is/academics.html Is it possible to pursue a phd in Semiconductor Devices/VLSI/Device Physics after this? Or, an MS in...

Homework Statement If a sample of pure silicon at 300 Kelvin has a resistivity of 950Ωm, and if the electron-to-hole mobility ration is 3:1, with the electron mobility equal to 0.12m2V-1s-1, what are the intrinsic hole and electron concentrations? Homework Equations I know resistivity...

Greetings everyone, I need information about how semiconductor interacts with electromagnetic radiation, the absorption, scattering, transmission and reflection properties of semiconductors. I also need to associate this information with free charges or bound charges. I would be grateful for...

what is it ? please explaining the physical operation of semiconductor diode (pn junction).

If I have a semiconductor junction of p-i and an electric field applied to it in forward bias, will the current flow?. How is the depletion region formed in intrinsic region since there are no free carriers there.What will be the electric field distribution through the intrinsic region?

Hello! I am trying to carry out wavelength depended photoconductivity experiment to a semiconductor thin film material. I use keithley 2400 sourcemeter. I do apply voltage to the sample under pressure and read the current. My problem is when i apply a constant voltage to the sample i see that...

Homework Statement The resistivity at room temperature of intrinsic silicon is 2.3*103 Ωm and that of an "n" type extrinsic silicon sample is 8.33*10-2Ωm . A bar of this extrinsic silicon with 50*1000 mm has a steady current of 100μA across it. The voltage across the bar is found to be 50...

Homework Statement A certain doped semiconductor at room temperature has the following properties: no = 9 x 1014 / cm3, po = 4 x 1014 / cm3, μe = 800 cm2 / V-s, μh = 400 cm2 / V-s, and (Dh\tauh)1/2 = 10-4 cm. If an electric field is applied, what fraction of the resulting drift current flow...

Suppose there is a semiconductor with Fermi energy $E_f$ and that there are $N$ bound electron states. I'd like to know why the mean number of excited electrons takes the form \bar n(T)={N\over \exp\beta(\mu-E_f)+1} where \mu is the chemical potential. ____ I can see that the Fermi...

Please help me understand the following (general) statement, referring to electrons in a full valence band of an n-type semiconductor: "An electron filling up the last empty state in the valence band will in doing so prevent the other valence electrons from reducing their energy through...

Homework Statement The conductivity of an intrinsic silicon sample is found to be 1.02 mS.m-1 at 297.2 K and 2.15 mS.m-1 at 307.9 K. What is the bandgap energy in silicon? Homework Equations ni = Ns(e^{\frac{-E}{2kT}}) \sigma = eni(μp + μn) The Attempt at a Solution I'm having...

Before I ask the question, let me explain a little bit about myself. I graduated just over a year ago with a bachelors in Physics, and am now starting my first semester of grad school in Energy Engineering. I have been out of practice, and am facing major struggles getting back into my...

Why n*p always equal to ni square?? (semiconductor) Hi, For you guys who studied semiconductor physics must be familiar with the equation: np=ni2 I can understand why this is true for the intrinsic case (the broken bonds would always provide electron and hole in pairs ) But why is this...

Hi! I study semiconductors and I am confused with the bonding picture for semiconductor crystals. For example, it is said that in Si crystal one can find covalent bonds. In the most books this bonds are shown like that: 2D crystal structure where lines between atoms are a covalent bonds, each...

Homework Statement rho(x) = 0 for x >= Xo and x <= -Xo rho(x) = ρ1 for 0< x < Xo rho(x) = -ρ1 for -Xo < x < 0. The last two rho's are constants. Electric field = 0 for x> Xo and x < -Xo. Find E for -Xo< x < Xo Homework Equations I used the ∇. E = ρ / epsilon The Attempt at a Solution...

Homework Statement The drift current in a p-n junction is 20μA . Estimate the number of electrons crossing a cross section per second in the depletion region. Homework Equations Drift current is the current that occurs due to formation of holes and electrons in the depleted region from...

why p type semiconductor is electrically neutral and what is the concept of drift current?

Can a hole go to conduction band? In p-type, the hole is above the fermi level, lower than conduction band, higher than valence band, how can this be happened? And will this happen when the p-type is at 0K

Please I need help to understand how diffusion current can occur in a circuit that contains an N-type or P-type semiconductor without being connected to an electric souce such as a battery.And how can both drift and diffusion current occur when the circuit is connected to a battery?

In intrinsic semiconductor, electrons jump into conduction band, a hole is left in valence band. My question is the above statement correct? I though the hole is something we imagine, how to say the hole is in the valence band? If I said an electron is in valence band, is that implying that...

Hi all, when we shine light on semiconductor surface with white light, superband gap transition occurs (VB to CB). Also we have surface state (SS) too, so there is probability of transition from VB to SS and SS to CB as well. The time transient of this surface is similar to charging of a...

Hi, I have a question regarding the change in charge carrier concentration change. For a given semiconductor, say Silicon, when it is not doped, it is easy to understand that {n_0} \times {p_0} = n_i^2, however, on doping with donors to form a n-type semiconductor, we have {n_0} \approx...

Homework Statement The electron concentration in silicon at T = 300K is: n(x) = 1016e(-x/18) cm-3 where x is measured in μm and is limited to 0 ≤ x ≤ 25. The electron diffusion coefficient, Dn = 25 cm2/s and the electron mobility is μn = 960cm2/Vs. The total electron current density is...

Look at the picture... Here current is flowing through a semiconductor... First think about holes... The holes will pile up on the upside... But if you think about electrons then the electrons also pile up on the upside... What's wrong here? Is it wrong because it is more appropriate to...

This question is about seebeck effect. If the movement of hole(positive charge) happens because of electrons moving in opposite direction, how is the heat carried by hole when one side of p-type semiconductor is heated? Is it from lattice vibration?

Homework Statement Determine the total number of energy states in silicon from the edge of the conduction band to Ec + kT for T = 300K. Homework Equations N = \intg(E)dE The Attempt at a Solution I'm pretty sure I know how to do this one. The only problem is, when I get to the...

Can anybody explain... what makes silicon indirect band semiconductor? thanks in advance Vani

Dear physics forums users, I'm reading a paper saying "For hole density p\sim 10^{17} - 10^{18}/cm^3, the screening length in silicon, \lambda_{Si}, is ~1-2nm." For this, the paper references Sze's, Physics of Semiconductor Devices. I'm unable to find the formula by which the authors seem to...

Hi, I just read a paper about charge transport in organic semiconductor. There, it was mention that from electrochemical experiments, it is well known that after the removal of one electron from an individual molecule, more energy is required to remove a second electron. I'm still confuse...

I would like to have at least a vague idea how coherent is light from an inexpensive 1 mW red semiconductor laser which I have. I tried to find the manufacturer using Google, but I haven't found it. I would like to know the coherence length and the degree of spatial coherence. Is there...

Hi everyone, I have a question here on what cause doped semiconductors to conduct. (such as Silicon with some As present, this is one atomic number higher) On my chemistry book, it says As covalently bond with 4 Si atoms as Si does, so the lattice is preserved, and 1 of its valence electron is...