Doping Definition and 61 Threads

Some post involving diodes made me reconsider pn junctions, with I first learned almost 40 years ago. Coming from a chemistry background, something always felt strange, but I could not tell what. Now I realized: While e.g. Gallium arsenide is a semiconductor itself and can be described roughly...

I know in RVB theory that neighbouring Copper atoms form singlet pairs via the superexchange "force". Upon doping with holes, these neutral singlet RVB pairs become mobile and charged and are able to superconduct. I know that the resonating valence bonds are in the copper 3d(x^2-y^2) orbital and...

I'm an EE with only a surface knowledge of solid state. I know this forum is mostly for students but I don't know where else to find a lot of physicists. Also, please forgive me if this is a dumb question. For a circuit I want to build, I need a transistor that can conduct > 10,000 A, but does...

Hello there, I have derived the expressions for electric field and potential to be the ones above, then for continuity at ##x = 0## I set the electric fields and potentials to be equal to yield the expressions: $$Sx_p^2 = Kx_n^2$$ $$V_{bi} = V_n - V_p = \frac {q}{3\epsilon} \left( Sx_p^3 +...

I do not understand why that is the case. Is there any intuitive explanation for it? Thanks

My question for now is as follows: Why does a high doping concentration causes a decrease in the thickness of depletion region. Any help will be highly appreciated! Thanks a bunch Regards!

Completely lost on this question. Any help would be great, even a direction to start moving would be helpful.

Hi all, So I'm confused how do I do this question when I add boron atoms. This is my take/attempt on this question though. Since there are much more boron atoms per cubic centimeters as compared to the number of holes, can I assume that p = ##3*10^{17}## now, and simply find n by using np=ni^2...

Summary: why do group 15 share the same conduction band as the silicon atoms. In a n type extrinsic semiconductors the atoms of silicon are doped with the atoms of a gr15 element to increase the number of valance electrons in the semiconductor. But the reason given to me by my teacher and what...

Hi all - This is pulled from a past paper - Homework Statement I'm only going to state the components that I find challenging of this problem - The rest will be attached in my solution set. Essentially - given an intrinsic semiconductor comprised of group II-VI elements. Upon doping with group...

Homework Statement Which one of the following describes the result of doping in semiconductors? a. The impurity provudes additional energy states within the conduction band b. More electron - hole pairs are introduced as a result of doping c. For n - type semiconductor, the number of "holes" in...

I have a pressing question, but I don't exactly know how best to articulate, or where. I am a wafer fab operator in the semiconductor industry. I usually operate ion implanters. The highest energy ion beams we use are a little over 3.5 MeV. As an aside, I am looking for a way, given that, to...

Homework Statement Homework EquationsThe Attempt at a Solution I think before getting the steady state, after doping there are more electrons in n-region and there are more holes in p-region, so the more electrons go towards the p-region and more holes go toward the n - region. Consequently...

In an unbiased p-n junction, how does increase in doping affect the width of Depletion Region? I read somewhere that width decreases as increase in carrier concentration leads to more recombination of majority carriers with oppositely charged ions of their depletion regions leading to a...

Is doping only to form an electric field in depletion region? Somehow I'm confused as far as I'm reading right now, the doping-generated carrier never discussed its role in the solar cell (other than leaving the ion and causing an electric field). Is not the number of carriers generated by...

In a degenerate n type semiconductor, when the doping concentration has a gradient(say -ve gradient), then how fermi energy level and intrinsic Fermi energy levels will depend upon the concentration gradient? ~If anyone knows anything about it, kindly help.

As an electronic engineer I am not an expert on semiconductor physics but I think I understand the basics of energy band diagrams reasonably well. It all fits together fairly neatly with the normal textbook assumption that we are looking at pure N-type or P-type doping. The problem I have is...

Hi. If a metal is very pure but still has other elements in it like this: -1 or 2 at 500ppm, 1 at 150ppm, 2 or 3 at 20-30ppm, 1 or 2 at 3-5ppm. Which are manufacturing impurities and which are deliberate doping? Are the 500ppm doping?

Hi there Im working in a solid state lab I have a semiconductor, let's say 'AB' nowim trying to dope it with a new element 'C' to form 'AB(1-x)Cx' im using bridgman technique for this purpose,,,that is heating all the ingredients together now the problem is that the element C sublimates before A...

Once synthesized, can YBCO be melted down to add more material or change the doping and still result in a functional superconductor?

The book I'm reading is discussing the physics of semiconductors. I'm having a hard time understanding a passage in section introducing n-type semiconductors. (Phosphorus is used as the impurity) The book says: "At normal operating temperatures, this extra electron breaks its bond with the...

Homework Statement Hello, I have to estimate the junction depth and layer thickness from the graph I am given. I know that when Phosphorus and boron are crossing, at this point is the Junction depth. What about the oxide layer grown, how would you estimate its thickness? For the second graph...

Homework Statement A sample of germaium has an acceptor concentration of Na=10^17 and a donor concentration of Nd=0. Calculate the intrinsic carrier concentration, majority carrier concentration, and Ef-Efi. Use T=400 Homework Equations No*Np=ni^2 Nv=Nv*(T/300)^3/2 Nc=Nc*(T/300)^3/2 ni^2=Nv*Nc...

Homework Statement Si atoms get doped inside GaAs to a concentration of 1.5*10^8 . Assume that the silicon atoms are fully ionized and that 35percent atoms replace gallium and that 65% of the added atoms replace arsenic t=300k Fnd the acceptor and donor concentrations Calculate electron /...

Hi, I understand that a n type doping will increase the number of electrons, and those electrons will go to the conduction band since the valence band is already filled. I don't exactly understand the effect on the bandgap. Thanks!

Homework Statement (a) Show law of mass action. (b) Find dopant concentration and hole concentration.[/B] Homework EquationsThe Attempt at a Solution Part(a)[/B] Bookwork. Part(b) Letting the doping concentration be ##D##, we have: D = n - p For ##I = n_{intrinsic} = p_{intrinsic}##, we...

Homework Statement we look at a silicum n++ p+ n transistor. given: NE= 1,0×1018 cm–3; NB= 2,0×1016 cm–3; NC = 2,0×1015 cm–3; here E stands for the emitter, B for the basis and C for the collectorHomework Equations a. calculate the distance in eV from the fermi-level to EFi for the emitter...

I am interested in creating phosphors for electroluminescent panels and from what I've read, one of the most common compounds is copper-doped zinc sulfide (ZnS:Cu). I've figured out how to create the zinc sulfide through a simple combustion synthesis reaction but it is the doping part that I...

Homework Statement The figure shows how a resistor in an integrated circuit made of silicon has been created by doping with gallium with the concentration ##5\cdot10^{22} m^{-3}## in an area that since before contained arsenic with the concentration ##1\cdot10^{22} m^{-3}##. The following...

Could anyone please explain why doped semiconductors show decrease of the bang gap in comparison to the pure semiconductors. Web/literature links to relevant information will be appreciated. Thanks.

How is it that certain electronic goods are designed to fail? Planned Obsolescence is just that, planned. So what goes into designing failing systems of computer? Hypothesis: Perhaps there are defects in the n and p-type doped semiconductors. The lattice entropy increases over time producing...

Homework Statement So in one of our practice problems it states that as we increase the doping concentrations, the result will be a decrease in mobility. However, I thought that when you increase doping concentrations, there will be a higher concentration of carriers available for...

I'm aware that you "dope" them with phosphorous for n-type and boron for p-type (I'm aware other materials can be used and other dopants are preferred in other situations). My question is exactly how is this done? Temperature, Pressure, Sputtering, etc.A white paper or something of the exact...

I want to know ... what happens to silicon when some impurity is added to it. Where does silicon goes??

I've read that electron doping in certain materials can lead to higher permittivity (for example, Nb in TiO2). This is a little confusing to me, as permittivity decreases with conductivity (see http://en.wikipedia.org/wiki/Permittivity#Lossy_medium). Can anyone explain this to me? P.S...

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...

I am reading Analysis and Design of Analog ICs by Gray and Meyer. In Ch. 2, they describe using MOS technology for fabricating on-chip capacitors. First and foremost, what exactly does surface potential mean in the context of semiconductors? Quoted from Gray and Meyer (5e), Page 149...

Hi I am using Quantum ESPRESSO v5.0.1 for my dft calcultaions. For doping in rutile tio2, I have replaced a nitrogen atom in the position of Ti atom. But when I view the input structure through xcrysden software, the nitrogen atom didnt form any bonds with the near by atoms. What could be the...

Dear forum, in a diode semiconductor, the N region is rich in electrons. The P region is rich in holes. Is the number of extra electrons in the N region equal, larger or smaller than the number of holes in the P region? If so, why? Also, in the N region, it is said that the majority...

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...

Curious what people's opinions are on this. Does anyone have a link to the investigation and evidence. http://www.reuters.com/article/2012/08/24/us-cycling-armstrong-doping-idUSBRE87N03N20120824

I'm reading up on semiconductors and there seems to be a few fundamentals I cannot find answers for if anyone can help? I understand that n-type substrate is doped with a donor and p-type substrate is doped with an acceptor creating excess electrons and holes. When you put the p-type and...

hi.. please tell me that 1) why some materials like ZnO, SnO, Pt, etc r sensitive to gases and others like Si, Ge, InP, GaAs, etc r not sensitive to gases. 2) how doping increase the sensitivity of a certain material to certain gases.

Are there any other atomic elements that are capable for doping apart from the trivalent and pentavalent atoms? If any why is it not preferred over boron and arsenic?

Homework Statement The problem is what would be the effect on the width of the depletion region of an unbiased PN junction on the doping levels of the P and N sides Homework Equations This is a conceptual question. There is no equation involved. The Attempt at a Solution Increase...

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Hi just a quick question, does the type of impurity (as long as its from group 3 or 5 respectively) used in doping a semiconductor matter in terms of its activation voltage or is it just down to the level of doping? So for instance a would say a silicon semiconductor doped with 1 to 10,000...

Can someone explain to me in detail formation of depletion zone and doping. I thought i understood this but it confused me when it came to this depletion zone. If u dope silicone with a substance with 3 valence electrons this forms a hole right? How does atom then behave? Does it polarize...

1. A Silicon wafer is doped with 2*10^16 cm^-3 Boron and 10^16 cm^-3 Phosphorous atoms. Calculate the electron and hole concentrations, the Fermi-level and the resistivity at room temperature I have no idea how to work out the first part of this question as my lecture notes are lacking in...

I'm reading an article that has n+, p+, and p doped silicon wafers. http://iopscience.iop.org/0953-8984/10/44/001" I hadn't heard of n+ or p+ before, just n and p. I noticed in the article that n+ and p+ had really low resistivites (10^-2 Ohm-cm) and p had a resistivity of about 10 Ohm-cm. So...