boyfarrell

286 reputation

bio	website	daniel.farrell.name
	location	Tokyo, Japan
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visits	member for	2 years, 4 months
	seen	Apr 22 at 10:37
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I know how to use the grey square -- do you?

	286 reputation	bio	website	daniel.farrell.name	visits	member for	2 years, 4 months
15 badges		location	Tokyo, Japan		seen	Apr 22 at 10:37

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Apr 2	comment	Erogodicity in a Monte Carlo simulation Ergodicity is a description of a system which has filled all degrees of freedom equally. For example, if you use MC method to simulate gas molecules, with constant initial velocity. The system will be ergodically distributed when the velocity follows the Maxwell-Boltzmann distribution. This is my understanding I'm sure there is a better definition involving entropy. Breaking this condition sounds like it implies a decrease in entropy.
Mar 29	comment	What are the various physical mechanisms for energy transfer to the photon during blackbody emission? I think about it something like this. The material has a temperature, which means that the atoms are vibrating (phonons). The phonons are coupled with the electron system and so the phonons and electron reach an equilibrium. Electrons are charged particles so they can loose (and gain) energy by optical transitions which is results in black body radiation. So I think that electron excitation and relaxation are the source of black body radiation. But how they couple will the lattice is also important. A nice question.
Mar 26	comment	2D quantum well energy spectrum (analytical vs numerical) Are you following a particular text, that would help us understand your code? I just want to check something. Quantum wells have a confining potential only in one dimension, the others are "in plane" unconfined directions. For example, if this was 2D box of semiconductor material I wouldn't expect 1D quantum well solutions. Maybe this could be an explanation? Or maybe it's just a case if using different definitions.
Mar 26	comment	Modeling incoming solar radiation Take a look at the SMARTS atmospheric model and associated documentation, it might have the clues you need. nrel.gov/rredc/smarts
Mar 23	comment	If light is linearly polarized, does it have some spatial extent? If instead we talk about a wavepacket of photons (which has some length) does it make sense to also talk about a "height"? Just curious.
Mar 12	comment	Ionized Depletion Region, Why aren't those charged being excited? Sorry I don't follow. Let's finish the discussion here, this comment thread is getting ridiculously long. You question sounds like it should be a new question. Ask it and make a diagram to illustrate your point.
Mar 12	comment	Ionized Depletion Region, Why aren't those charged being excited? Yay! You got it! My pleasure, every time I am forced to think about the pn-junction I learn something new, so thank you for your question. The pn-junction is actually surprising complex piece of physics (in concept and computationally). Keep on asking question if you get stuck.
Mar 11	comment	Ionized Depletion Region, Why aren't those charged being excited? No! They are not in the bands, they are in the bandgap! Where I have drawn the acceptor/donors is accurate. They are not periodic therefore they don't form a band. They are just discrete energy levels near the respective band edges which provide additional carriers.
Mar 11	comment	Ionized Depletion Region, Why aren't those charged being excited? Right! You can think of that way. On the n-side to ionize a donor the electron only needs several ~kT, however on the de-ionise an acceptor (release an electron to the conduction band) on the p-side the electron needs about ~40kT. The same thing happens when you consider it from the "hole perspective".
Mar 8	comment	Ionized Depletion Region, Why aren't those charged being excited? Sorry I don't follow.
Mar 7	comment	What is the effect of refractive index of an object for imaging? Can you draw a diagram, it's hard to understand your question.
Mar 6	revised	Ionized Depletion Region, Why aren't those charged being excited? Clearing up the answer a bit.
Mar 6	revised	Ionized Depletion Region, Why aren't those charged being excited? Updated diagram.
Mar 6	awarded	Commentator
Mar 6	comment	Ionized Depletion Region, Why aren't those charged being excited? See the update above.
Mar 6	revised	Ionized Depletion Region, Why aren't those charged being excited? Added diagram.
Mar 4	revised	Ionized Depletion Region, Why aren't those charged being excited? added 85 characters in body
Mar 4	comment	Ionized Depletion Region, Why aren't those charged being excited? Yes, but the opposite is happening on the n-side. The n-side is ionised and wants to capture an electron from the valence band, therefore the energy gap is the same ~1eV.
Mar 4	revised	Ionized Depletion Region, Why aren't those charged being excited? Removed comment to the author.
Mar 4	comment	Ionized Depletion Region, Why aren't those charged being excited? I think the rate will be quite low because the electron (from the p-side acceptor) would have to acquire enough thermal energy to reach the conduction band of the material (about a ~1eV jump). The thermal energy at room temperature is much lower ~25meV, so I imagine that once acceptor captures the free electron (from the n-side) it will be quite stable.