Questions tagged [charge-carrier]
26 questions
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What is "free charge" in the macroscopic maxwell equations?
Wikipedia states the macroscopic Gauss' law as $\nabla \cdot \overrightarrow{D} = \rho_f$, where $\rho_f$ is the charge density of free charge carriers.
I understand that conducting electrons in a metal are considered free charge carriers, while the…
Frikandel
- 41
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2
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1 answer
Doesn't charge carrier density depend on the charge of the metal?
Imagine a sphere and wire charged to $10 \ \text{V}$ is connected to a neutral sphere. There are more charge carriers on the $10 \ \text{V}$ sphere and wire, so surely more electrons flow through the wire when the connection occurs. Why do we still…
Lewis Kelsey
- 217
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Is it possible to say that entropy would affect the charge transportation?
I noticed there are a few papers from Dr. Karuppuchamy Navamani, for example:
Generalization on Entropy-Ruled Charge and Energy Transport for Organic Solids and Biomolecular Aggregates
Theoretical modeling of charge transport in…
Jack
- 57
2
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2 answers
Semiconductor Physics: Depletion region in PN junction
We know that a depletion region of a PN junction is that region in which there is no free charge carrier i.e. electrons or holes but only contains Ions of positive and negative charge.
We know when we apply forward bias, then the dominant current…
Suraj Kumar
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2
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Charge carriers type: contradiction between Hall effect and Seebeck effect, how to resolve it?
On one hand the Hall effect consists of a voltage that arises when an electric field and a perpendicular magnetic field are in a material. This makes the charge carriers (electrons or holes) under the action of Lorentz force which deviates the…
2
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1 answer
Reverse recovery current of a diode
When the diode is in forward bias phase and suddenly we apply a reverse bias voltage, the diode takes time to be fully blocked because of the excess of minority charges that are stored in P and N region. Thus a reverse current appears in the diode…
Tonylb1
- 527
1
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Maxwell's Equations Relativistic Interpretation
I've seen similar questions asking about expressing Maxwell's equations with relativistic formulation, but my question is about the physical interpretation it may give for their conventional form.
I'm only familiar with the intuition of special…
Lambda
- 265
1
vote
1 answer
Potential difference between two hollow spheres and amount of current flow
If two Hollow Spheres with radius $r_1$ and $r_2$ have charge $q_1$ and $-q_2$ in them respectively(charges are evenly distributed in the surfaces).The spheres are separated by a distance d .Now We connect a conducting wire from one sphere to…
MD Hossain
- 37
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Why doesn't the classical model of electrical conduction work with iron, cadmium and bismuth?
My textbook says this:
In most metals, the charge carriers are electrons and the charge - carrier density determined from Hall - effect measurements is in good agreement with calculated values for such metals as lithium (Li), sodium (Na), copper…
Cross
- 3,360
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1 answer
What makes of a current in solidstate/semiconductor physics?
If there is some incoming light that has hit electrons of a N-type doped silicon and broke loose these electrons from their covalent bounds and excited them to the conduction band and also excited the electrons in the donor energy level to the…
bob todd
- 13
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1 answer
In an intrinsic semiconductor, are there the same number of carrier electrons and holes? Or this is just exclusive for silicon?
I am working with some polymers that behave like semiconductors when they are plugged into the current.
I am calculating the mobility of these polymers and I need the value of the current density (J) in order to achieve it.
I have found that the…
1
vote
0 answers
Where can I learn about a history of holes?
Holes are quasiparticles that were historically brought to explain semiconductor physics with extra benefit of simplifying the counting of electrons.Who gave the first idea and how did it develop gradually?I searched in the internet,wiki(or other…
Manas Dogra
- 1,108
0
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Deriving Faraday's law from a special case, do we consider Lorentz force on electrons only or Laplace force to derive it?
In this electromagnetism class, professor derives Faraday's law from a very specific case (he specifies Faraday's law is a kind of axiom in physics, but that in this very special configuration, one can "derive" it).
The configuration is: we have a…
niobium
- 754
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How is the number of charge carriers set free in an x-ray detector proportional to the energy of the incoming photon?
I'm a chemistry undergrad student and I've been doing some research into the ways light is generated and detected at different parts of the spectrum (for the purposes of better understanding practical spectroscopy). My questions comes from this…
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1 answer
Current Inside the Depletion Region Forward Biased PN Junction
For a forward biased PN junction, we assume the hole and electron currents are constant inside the depletion region when there is no generation or recombination in the depletion region (shown from the figure off of Neaman's book). If we only…
Abe
- 83