Recent content by bpsbps

I'm not entirely certain that I understand the meaning of "recombination velocity" but if you mean what is the velocity of charge carriers that are recombining then it would be the Fermi velocity.

Assuming that we're only talking about "shallow dopants"... You're on the right path... With a pentavalent impurity where does the extra electron go? It is loosely bound to the impurity atom and is delocalized in the lattice in the vicinity of the impurity. The charge can be easily ionized...

The simplest explanation is that there is a small amount of impurity, but it is a strong x-ray scatterer so there are large peaks in the measured spectrum. Remember that the peak height only indicates the relative mass fraction if the scattering power of the compounds being compared are the...

How do you define the plane? There is a family of planes that are parallel to each other. I can draw a [001] plane in a SC lattice that contains no lattice points.

The question is ambiguous. It can mean what is the "density of lattice points" (units cm^-3)or "area density of lattice points on the [211] planes" (units cm^-2).

Consider that there is one lattice point per unit cell. So there is one lattice point per volume of a unit cell. Then what is the volume per lattice point? This is the density of lattice points.

The word "really" is an adverb that modifies "is". Normally we put the adverb either (1) In start of the sentence: "Really, how transparent is the universe?" (2) Between the subject and the verb: "The universe really is transparent." In the given example, because the...

Chinese. Chinese universities are on the cusp of being competitive with US schools. Very soon schools like Tsinghua will have a better reputation than some of the US state universities. Currently Chinese journals are mostly printed in English. As the Chinese universities rise in...

Most of the x-rays are coming from "bremsstrahlung" radiation. When the accelerated electron bangs around the metal target is loses energy and this is given off as radiation. The highest possible x-ray energy is equal to the initial kinetic energy of the incoming electron this would happen...

It depends on your interests. You might do fine with a minor. In addition to my standard Engineering math (Calc I II III + ODEs) I took PDEs, Group Theory, Linear Algebra, graduate level Statistics, and graduate level Engineering Analysis I. The only class that I didn't take, but should have...

The only advantage is if you can do mathematics better and subsequently do better at physics. Of course you can always study "off the books" so that there is no record. But if you don't study hard then you won't learn the material -- i.e. if you're working as hard as you need to learn...

The best way to land a job is to have a job... You should look for an internship with a local company where you can prove yourself able to produce. To me a BS in physics means next to nothing. I've seen awful workers graduate with a BS and a near 4.0 GPA. It is your recommendations that...

I think you lost me somewhere in this story... You have two atomic structures that are amorphous and you want to compare them? Is that it or is there more?

A plane wave in real-space is a point in k-space. The k-value of the point is 2 pi / lambda where lambda is the real space wavelength of the plane wave. Perhaps I do not understand correctly what you are asking.

I think you're getting the horse in front of the cart. Wait to see if you enjoy and are good a physics. Then decide on grad school. Then decide on a career. Regarding NASA... you can do better, I hope. From my work experience I'm much more impressed with NRL than NASA. There is much...