Author Topic: Calculation the transport properties of graphene  (Read 33971 times)

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Offline esp

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Re: Calculation the transport properties of graphene
« Reply #30 on: January 16, 2012, 22:52 »
Why do you keep referring to my structure as metallic?  I created an AGNR which should be a semiconductor, and indeed I have checked and there is a significant bandgap ... also why 1d?  I make a nanoribbon, isnt that 2d?

Offline esp

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Re: Calculation the transport properties of graphene
« Reply #31 on: January 16, 2012, 22:56 »
also about "the box" ... i assume you are talking about the unit cell padding ... should i just make this arbitrarily large then?  Is there any information on this?  I am sorry i don't know what "the box" is ... I am guessing this is the region of calculation for various things, set by this unit cell padding parameter from the gui?

Offline Anders Blom

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Re: Calculation the transport properties of graphene
« Reply #32 on: January 16, 2012, 23:09 »
You are right, but metallic is not the point :) The point is that it's perfectly periodic. So, once you increase the bias large enough to make it overcome the bandgap, the semiconductor turns "metallic", and the same argument applies.

Offline esp

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Re: Calculation the transport properties of graphene
« Reply #33 on: January 16, 2012, 23:20 »
I see ok I just want to make sure I understand correctly. 

On the point of IV curves .. there are certainly many papers that report IV curves for what they term "perfect" GNRfet structures ... for example: http://ieeexplore.ieee.org/search/srchabstract.jsp?tp=&arnumber=5567164&openedRefinements%3D*%26filter%3DAND%28NOT%284283010803%29%29%26searchField%3DSearch+All%26queryText%3DGraphene+Nanoribbon+FETs%3A+Technology+Exploration+for+Performance+and+Reliability

Now, you say that ATK considers the ballistic regime ... I am not sure if I understand well enough, but my understand was that electrons will only move ballistically if you do not consider higher order effects in the structure, like phone scattering, nearest neighbor interactions, etc ... are you saying there is a limitation in ATK that will not allow me to produce a plot like those in the paper, or is it that I am not in full understanding here ... ?

In other words, my understanding was that ATK can calculate IV curves at the most sophisticated level, including higher order interactions and effects .. is this the case?  Is it that the way I made it, my structure is too simplistic?


Offline esp

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Re: Calculation the transport properties of graphene
« Reply #34 on: January 17, 2012, 07:59 »
maybe my problem is that i have no introduced any doping so i have only one type of GNR, sorry i will revisit the structure

Offline kstokbro

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Re: Calculation the transport properties of graphene
« Reply #35 on: January 17, 2012, 10:02 »
ATK will include all elastic scattering effects, like scattering with a doping atom or other imperfections in the structure.

It will not include inelastic scattering effects, where the electron looses energy, like in the scattering with a phonon.

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Re: Calculation the transport properties of graphene
« Reply #36 on: January 17, 2012, 10:03 »
ok thank you