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Holes are really electrons that are jumping from one vacant pkace to another. So, just like the electron current, at one terminal they are injected into the semiconductor, and at the other taken away by the power source. In some fields the two terminals are aptly called source and drain/sink - using the analongy with flowing water.


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The band gap of crystalline Si at 300 K is 1.12 eV. Here is an authoritative source for band structure information. Crystalline silicon is an indirect band gap semiconductor. Doping does not change that. If I had to guess the source of the confusion, it's direct vs indirect bandgap. If you look at the spacing between the bands at $\vec{k}=0$, it's about 3.4 ...


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If a perfect semiconductor/insulator is at zero temperature, than indeed all its electrons are in the valence band, and exciting them to the conduction band requires, as a minimum, the gap energy, $E_g$. If a uniform electric field is applied, then, obviously, there will be degeneracy between the valence band and the conduction band states, separated by ...


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Free electrons in semiconductors are not real, but quasiparticles. In fact, one often models semiconductor heterostructure as an effective potential imposed on electrons in an effective mass approximation. So in terms of the electron mass, g-factor and other properties, these electrons have the same qualities as they would have in a bulk material.


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Yes, we can calculate the electron lifetime. The main difficulty comes from accounting for the appropriate relaxation mechanisms, relevant to specific material and conditions (additional to the obvuious radiative recombination). To mention the principal ones: Radiative recombination: electron recombines with a whole, emitting a photon. Auger recombination: ...


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Answer 1. No. Once the circuit is turned off the holes become empty and n side will have "extra electrons". Answer 2. When in use, the electrons travel by jumping from hole to hole. So, yes, the atoms get an extra electron while in use. The important thing to remember here is the charge in the nucleus. The "hole" and "extra electron&...


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Fermi wave length is $$\lambda_F=\frac{2\pi}{k_F}, \text{ where } k_F=\frac{1}{\hbar}\sqrt{2m^*\epsilon_F},$$ where the Fermi energy, $\epsilon_F$, is measured in respect to the bottom of the conduction band. The Fermi energy of a (n-doped) semiconductor is typically rather close to the band edge. In fact, by controlling the doping, it can be made it as ...


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One things a magnetic field does is exert a sideways force on a current. This tries to squeeze moving electrons closer together on one side of a wire. This raises their potential energy on one side and reduces it on the other. A difference in energy per electron is a voltage difference. This voltage difference from one side to the other is called the Hall ...


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The picture the author is trying to convey is that if you build a covalently-bonded crystal lattice out of atoms, then the discrete energy levels which characterize the isolated atoms split apart into continuous energy bands. The highest occupied level in the isolated atom becomes the valence band, and the next-highest level (which is unoccupied) becomes ...


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