Re: problem while running Quantumwise

[brajesh]

Respected Sir

Thank you sir for your reply

Sir will It possible to make 20 nm gate length graphene transistor in quantum-wise. Sir I am trying to make graphene transistor around 10nm in quantumwise than its freezes.

[Anders Blom]

What freezes (and how), the calculation, or the GUI while building the structure?

[brajesh]

Respected Sir

The GUl is hang if we make structure little big like (10nm graphene transistor) and it also takes more time in calculation.

I am working on graphene tunnel field effect transistor.Will it possible to make 30nm graphene tunnel transistor in quantum-wise.

Thank you

[Anders Blom]

The length by itself is not the only relevant parameter, the question is how many atoms are present. 20-30 nm gate length should not be a problem if you rely on periodic boundary conditions in the other direction in the graphene plane.

If you share the structure we can advice more specifically. You can email it privately if you don't want to share it, although we may publish the answer here for others too benefit, without revealing the structure of course, just the principles.

[brajesh]

Sir I made this for an example. I made graphene sheet with channel length 8.8 nm and electrode length around 0.7 nm. This architecture take time in GUI and calculation due to no of atoms.
Similarly I want to work around 20nm channel length graphene transistor and GUI implementation is difficult for that length.

We have quantum wise single user license. Will it be ok.

[Anders Blom]

Why have you repeated the structure in the B (Y) direction? The only effect is to make the calculation heavier... Always use the minimal cell and then use k-point sampling to model the periodicity. Of course, if you want to introduce defects, things get a bit more difficult.

How many atoms are in your structure? The GUI should be able to handle it, but you do need proper 3D hardware accelerated graphics. If you don't have that, you should upgrade to the latest video drivers and/or get a real 3D graphics card.

For a structure like this, tight-binding models will likely provide almost the same accuracy as DFT, so I would suggest starting with that - it will reduce the calculation time dramatically. Cf. http://quantumwise.com/documents/tutorials/latest/SlaterKosterModel/index.html/chap.carbonpi.html

[brajesh]

Thanking you sir

I will try to make device as you advise.
 
Sir I am also using NanoTCAD-ViDES tool to implement geometer and written reference code for graphene transistor have problem of convergence. Will you please help me to solve the problem in python code.

I am waiting for your valuable reply.