Gap Definition and 288 Threads

Gallium phosphide (GaP), a phosphide of gallium, is a compound semiconductor material with an indirect band gap of 2.24 eV at room temperature. Impure polycrystalline material has the appearance of pale orange or grayish pieces. Undoped single crystals are orange, but strongly doped wafers appear darker due to free-carrier absorption. It is odorless and insoluble in water.
GaP has a microhardness of 9450 N/mm2, a Debye temperature of 446 K (173 °C), and a thermal expansion coefficient of 5.3 ×10−6 K−1 at room temperature. Sulfur, silicon or tellurium are used as dopants to produce n-type semiconductors. Zinc is used as a dopant for the p-type semiconductor.
Gallium phosphide has applications in optical systems. Its static dielectric constant is 11.1 at room temperature. Its refractive index varies between ~3.2 and 5.0 across the visible range, which is higher than in most other semiconducting materials.

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  1. B

    Finding Gap Between Two Objects on Moving Conveyor

    I am needing to find the gap between two pieces of wood on a conveyor belt. I am new t this and am having trouble knowing what to Google to find the right formulas. I found one answer on here that helped a little, but it was dealing with two conveyors, and I am not sure if I adjusted the formula...
  2. L

    Admissions Academics gap: Looking for 2nd M.Sc Physics degree or a PhD Physics?

    Hi everyone, I finished M.Sc Physics by "Research" at a UK university during the academic year of 2015. I am an international student from India. As I did not do well in my oral presentation defending my M.Sc thesis (but it was not worst), as a result, I got a pass degree. Before the day or...
  3. MevsEinstein

    I Defining the Prime Gap function

    Hi PF! I created a function ##R(x)## that gives the gap between the largest two primes less than or equal to ##x##. To define it, I used this property: $$\pi(x+R(x))=\pi(x)+1$$ Which is true since the ##x## distance between ##\pi(x)## and ##\pi(x)+1## is ##R(x)##. If we solve for ##R(x)## we...
  4. godiswatching_

    What is the effect of a 1 cm gap on the magnetic field in a solenoid?

    Hey, I was trying to figure out this problem. I got (a) using B = mu * NI/L but I'm not sure how to start the part about the magnetic field in the gap after the solenoid is ripped in half with 1 cm gap. Thanks for the help!
  5. F

    I Gap between introductory physics & solid state physics?

    The left pic is the initial state and the right pics are 2 different descriptions for a metal under electric field E. Are the 2 on the right contradictory and which is correct?
  6. BalinesePhysicist

    Studying What to do in a gap year to prepare for a Physics + Math degree

    As the title says, I am now in a Coronavirus induced gap year. I have been accepted at a university, which for some reason requires us to do a double major. Hence I chose math as my second major alongside Physics since it has the most overlap, and I'm also very interested in theory. In school, I...
  7. yecko

    Engineering Can the efficiency of a solar cell with a single band gap reach 100%?

    I have tried looking up online with the photoelectric effect, it just mentioned the energy of the photon must have to equal to band-gap energy. Yet, it didn't mention if 100% can be reached in that case, or if a single bandgap makes any effect...
  8. M

    An accurate method to determine the band gap

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  9. R

    Admissions Applying for PhD with Low UG GPA and Gap Years

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  10. T

    How to make the most of a gap year during the Covid-19 era?

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  11. Rzbs

    I Importance of the energy gap in electronic transport properties

    In the solid state physics by Ashcroft & Mermin, in chapter 9 there is a paragraph that I would be grateful if anyone could explain it more for me. The paragraph is: As it said in chapter 12 it will be seen. I read chapter 12 but unfortunately I can't understand what exactly it want to say...
  12. T

    How to Measure and Calculate Band Gap of a Photovoltaic Device

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  13. J

    Modeling Uniform Field Gap Electrodes, Rogowski or others

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  14. J

    Uniform Field Gap (Rogowski profile) Electrode Design

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  15. Amitkumarr

    Chemistry Why Are Options B and C Incorrect for HOMO-LUMO Energy Gap?

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  16. Jehannum

    Gap in the market for a book on the Standard Model

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  17. jisbon

    Energy band gap when there is an electric field

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  18. S

    I Where exactly is the Hertzsprung Gap?

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  19. R

    Insight into the conceptual gap and how to fill it

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  20. J

    Engineering Calculating the gap of a parallel plate capacitor

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  21. A

    Mercury Seal Gap Size: Is it Possible?

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  22. E

    Why is the band gap in alloys such as GaAs less?

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  23. Alex Karatzky

    How to optimize spark gap Tesla coils

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  24. Alex Karatzky

    How to optimize spark gap Tesla coils?

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  25. G

    Stargazing What explains the Luna impact gap?

    I was reading in Sky and Telescope about the Lunar flash during the eclipse last week, and looking at the impact map (2005-2018) I was wondering why there is a 'gap' with no impacts down the middle. It seems rather unlikely that there would be no 'hits' here. Is this an artifact of the limb and...
  26. Cerenkov

    B The Spectral Gap and Quantum Vacuum Fluctuations

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  27. FlyingPhysicist

    Schools I'm forced to take a gap before uni, how will it affect me?

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  28. N

    A Band Gap Vs Pressure: Proskite Compounds

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  29. YoungPhysicist

    I Closing the Gap: The Evolution of CMS at CERN

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  30. G

    A Energy gap between energy bands in solid state physics

    I know that Bragg reflection in solid states at the edge of e.g. the first Brillouin Zone causes standing waves at these edges, which creates a gap between the energy bands. In this picture below you can see the probability density of a symmetric (+) and anti-symmetric (-) standing wave. The...
  31. multivac42

    Admissions A gap in biography in application

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  32. T

    Toroid with Air Gap magnetostatics problem

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  33. J

    Air resistance: cylindrical rotor in stator with air gap

    Hello, I am currently doing research on the aerodynamic properties of a rotating cylinder in a cylindrical housing. The cylinder represents a rotor in a electric motor. The air gap between rotor and stator is about 0.5mm. I'm looking for a theoretical analysis and calculation on the...
  34. Y

    Other Gap Year Physics Research for an International Student?

    Just got rejected by nearly all of my grad schools (one hasn't reply but the chance is pretty small). The funding is super harsh this year in my field and even worse for a student from China. Is there any way for an international student to take a gap year for physics research in the U.S? ( My...
  35. Alettix

    Magnetic field in the gap of a tapered torus

    Homework Statement Consider a toroidal electromagnet filled with a magnetic material of large permeability µ. The torus contains a small vacuum gap of length h. Over most of its length the torus has a circular cross section of radius R, but towards the gap the torus is tapered on both of its...
  36. S

    Energy Gap of 2 states in a deep rectangular potential well.

    What is the energy gap between the ground state (n=0) and the first excited state (n=1) of an electron trapped in a deep rectangular potential well of width 1Å?
  37. F

    Is Plate Capacitor Gap a "Non-linear" Medium?

    Could the space (air gap) between two DC charged parallel plates be considered to be a "non-linear" medium with respect to an EMF radiated by a coil contained within that space?
  38. alex1515

    Studying I'm 16 and want to study physics, should i take a gap year?

    I was fascinated with physics since i was 14, when i actually began my learning journey, i got into Newtonian mechanics and eventually learned some electronics and programming. Noticing the math that was involved, i decided to first get started with math before i proceed into learning physics...
  39. G

    I Relationship between the depletion region and the band gap of a diode?

    Hi, Lately I've been reading about a lab exercise in which Planck's constant is estimated using LEDs. Every procedure I've encountered states that the energy of an emitted photon (and by extension the potential across the semiconductor's band gap) is equal to the threshold voltage multiplied by...
  40. G

    Semiconductor resistor in series with a capacitor -- Energy gap

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  41. E

    MMF/Flux density across air gap for a salient pole

    Hi I am trying to understand the figure 2 I have attached to this post. From text: Ok, I get that the air-gap flux density varies in a sinusoidal manner, because the air gap length is not constant i.e. non-constant reluctance and hence non-constant magnetic flux density. What I do not...
  42. J

    Other What's the Best Physics Textbook for a Gap Year Review?

    Hi, I've just finished A Level Physics, and after a gap year I'm headed to do Physics at Exeter. I'm looking for a textbook or online course or something that has lots of A Level and (maybe slightly higher) Physics questions that I can work through over the course of this year. Does anyone have...
  43. LLT71

    Efficient Use of Spectrum: The Importance of a Safe Gap Between Channels

    If we have 300kHz bandwidth and every channel uses 100kHz BW, then theoretically we can have total of 3 channels that won't overlap. Why do we need to assign some of the bandwidth for "safe gap" between channels if they "don’t" overlap?
  44. L

    Astronomy/Astrophysics Gap Year/5th year of Undergrad

    Hello there, I am currently a senior undergraduate Astronomy and Astrophysics major at Villanova University. With the GRE and graduate school applications coming up I have been wondering if it would be beneficial for me to either take a gap year or to possibly take a 5th year of undergraduate...
  45. N

    Schools Should I take a gap year to self study before college?

    I was admitted to a very good undergraduate physics program (Columbia University), but I think I would like to take a gap year (defer my admission) to prepare my self better. I do feel a bit intimidated as I come from Colombia and I would prefer it if I could further my studies before going to...
  46. T

    Energy gap between orbitals and stability

    We know that the lower the energy gap between bonding and antibonding orbital the easier it is to break the bond making it unstable. However, in a conjugated double bond, the overlapping of wavefunctions cause the energy gap between the bonding and antibonding orbital go down. Then why...
  47. G

    What if gap is irregular in capacitor

    I don't have clear concept on voltage. I am a Mechanical guy. If the gap is irregular in large capacitor, how voltage is derived in theory. Using software I can divide the surface into many pieces and calculate voltage of individual small piece. I attached my problem.
  48. peroAlex

    Flux and Current of Magnetic Core With Air Gap

    I am a student of electrical engineering. This task appears in our textbook. However, there were no solutions provided. I tried understanding the task but got lost in the process. This is why I seek help here on this site. I would like to ask you for guidance and any sort of advice on how to...
  49. Sachin Desarada

    Physics 2 year gap after M.Sc , now want to do Ph.D

    I need help. I completed my post graduation in 2015 material science, now it nearly 2 year gap want to do Ph.D . How can i start . i don't have GATE score, how can i apply for Ph.D.
  50. V

    A Nanowire with charge neutrality in band gap

    I'm working on a finite element simulation of the electrostatic potential V(r) in and around semiconductor nanowires, based on solving Poisson's equation. While the details of the problem will follow shortly, the crux of where I run into trouble is that for nanowires it is important to include...
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