I am also confused about something from the textbook: it uses equations 2,3 and 4 above to define the relationship between \tau and I as being:
\frac {1}{\tau^2} = A^2 + \frac{4B}{qV}I}
I just keep going round in circles when I try to derive this from equations 2,3 and 4 :(
Hi there,
Not sure if this is in the best section, but here goes...
I'm trying to establish how a formula from a paper I have read has been derived. The formula is:
n=\frac{1}{qV} \int_0^I{\tau} dI
where n is the carrier density, q is the elementary charge, V is the volume of the...
Hi,
I'm trying to get my head around the concept of transverse modes as seen from the outputs of lasers. I'm really struggling to even visualise the concept. From what I grasp, the transverse mode represents the intensity profile of the output laser beam. However I just can't make the jump...
I thought I'd add my own little summary of the answers to my questions I got to with the help of jsgruszynski.
"if the channel has been pinched off, how can carriers readily flow between the source and drain?"
Near the drain, the inversion channel is 'pinched off'. However, there exists a...
Thanks again, TorKjellsson.
I think I just have to accept that what QM tells us can't be pictured neatly in my head by images of a couple of electrons with pointy arrows on them indicating their spin!
I think I understand as much as I actually need to understand, for now at least :P
Hi there,
I have a passing interaction with quantum dots and light emitting polymers as part of my research. I've been reading up on the physics of qdots and polymers recently. One thing that strikes me is that the existence of triplet states in polymers is mentioned, but not in quantum dots...
Hi Cthugha, thanks for your reply.
I'm able to follow the procedure you mention in terms of deriving the expressions that give the graphs shown in my first post. What I'm not clear on is a mental picture of what physically is happening.
I can understand the 1D quantum dots. Only quantised...
I've realized that the difference between the two is something to do with the fact that in the QW the electrons are only confined in 2 directions, which explains why there are allowed energy levels in between the quantised levels.
In other words, in the Z direction the energy levels are...
Thanks for all your help, but I fear that I'm getting increasingly out of my depth!
To be perfectly honest, I'm not even clear on the difference between S and m. S is the total spin, and m is...?
The more I go into this, the less I seem to understand. I'd thought that in the singlet state...
Hi there, I'm a bit confused as to the meaning of the following figure, for the quantum well case:
I understand that with the quantum dot, since the states are completely quantised you get the delta functions - states only exist at certain energies so the DOS at these energies is non zero...
Thanks for your reply TorKjellsson, but I'm still a bit lost. I can follow what you've written (I think) but I'm confused to the actual physical meaning of something like "|+ - > - | - +>"
To me, I understand that "m = 1 can only be "built" by |+ +> since 1/2 +1/2 = 1" in that in my mind there...
I hope someone can provide me with a really dumbed-down explanation of all this (preferably written in terms of electrons having spin "pointing up" or "pointing down". That's the level I'm coming in at).
I understand that in a singlet state there is only one state, which has total spin = 0...
Hi,
I'm getting myself confused about the physical meaning of Sz = -1, 0, 1
Does this mean that the triplet state can have three degenerate ms energy levels, with spin quantum number = -1 (i.e. two "spin down" electrons), 1 (two "spin up electrons") or 0 (spin up/spin down on the HOMO and...