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Messages - artingchen

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1
General Questions and Answers / how to set the dopants
« on: May 24, 2012, 13:50 »
hi, every body,

I want to calculate the doped semiconductor. As we know, the donor or acceptor impurities are charged, such as the P atom is positive ion after substituting the Si atom. So, How can I set up the simulation model in which the impurity atom replace the host atom ? I used the P or B atom simply replace the Si atom, and got the band structure which indicates the doped Si bulk acts as N or P type semiconductor. But, the Mulliken popular of the P atom show that the p atom is negtive ion. How to undertand this issue ? Should I make the doped P atom positive during the calculation ?

Any suggestion is great appreciated !

 

2
General Questions and Answers / Re: how to analysis the band structure of B-doped armchair graphene ribbons
« on: March 1, 2011, 10:15 »
Quote from: zh on March  1, 2011, 10:02
For boron-doped graphene, you may find many theoretical works in literature:
1) Panchakarla et al, Synthesis, Structure and Properties of Boron and Nitrogen Doped Graphene, http://arxiv.org/abs/0902.3077 or Advanced Materials, Volume 21, Issue 46, pages 4726–4730, December 11, 2009
2) Yu et al, Electronic Properties of Nitrogen-/Boron-Doped, Graphene Nanoribbons With Armchair Edges, IEEE TRANSACTIONS ON NANOTECHNOLOGY, VOL. 9, NO. 1, JANUARY 2010
3) Martins et  al, Electronic and Transport Properties of Boron-Doped Graphene Nanoribbons, Phys. Rev. Lett. 98, 196803 (2007)
4) Wu e tal, Light non-metallic atom (B, N, O and F)-doped graphene: a first-principles study,  2010 Nanotechnology 21, 505202
...
From these articles, you can catch some basic knowledges of the boron-doped graphene and these will be very helpful to analyze your results.

Basically, boron doping in graphene will introduce hole, namely, it is hole doping. This is why the Fermi level is shifted down in the B-doped armchair graphene nanoribbon and the calculated band structure shows a metallic behavior.



Can the high concentration of B atom account for this ?

3
General Questions and Answers / how to analysis the band structure of B-doped armchair graphene ribbons
« on: March 1, 2011, 06:24 »
hi，
I recently calculated the energy band structure of B-doped armchair graphene ribbons, but I did not know how to analysis it. I have enclosed the figure of energy band structure of intrinsic and B-doped armchair graphene ribbons. In that figure, the left figure is for intrinsic armchair graphene ribbons and the right figure is B-doped armchair graphene ribbons. obviously  intrinsic armchair graphene ribbons is a semiconductor, but  is it B-doped armchair graphene ribbons semiconductor ? Is that can be deduced from the energy figure ? B-doped armchair graphene ribbons seems a metal, am I right ?

can any one help me to analysis it ? any suggestion is appreciated ! thank you !

4
General Questions and Answers / why the fermi energ level locates blow the valence band ?
« on: December 12, 2010, 10:05 »
Hello, every body,

I calculated the band structure of doped graphene ribbon recently, but the figure I obtained confuses me. the fermi energy locats below the valence band when it is doped. the fermi energy is -4.37 eV for intrinsic GNRs but -5.07 eV for doped GNRs. can anyone help me to explain the phenomenon? any suggestion is appreciated. thank you !
the figure have been attached.

5
General Questions and Answers / Re: how to build the graphene nanoribbons?
« on: June 23, 2010, 10:54 »
Quote from: Anders Blom on June 23, 2010, 09:39
In 2008.10, the way to use the script is to drop it on the Builder, for instance. However, to make the kind of ribbon you want, you should change the parameters. If you just downloaded it, and dropped it directly, and it failed, probably the script got messed up somehow. Try to follow the tutorial, and if you fail at some point, let us know in more detail what you do, and how it fails, otherwise we cannot really help.
Ok, It works, Thank you Doc.Blom.

6
General Questions and Answers / Re: how to build the graphene nanoribbons?
« on: June 23, 2010, 09:27 »
Quote from: Anders Blom on June 23, 2010, 07:17
That script only works for VNL 2008.10 (and you need to look inside it and edit the details). In 2010.02 and 10.8, there is a built-in ribbon builder as part of the "Custom" builders.
Dear Blom,

I am using the VNL-2008.10, It is doesn't work ! I will try it agian. thank you !

7
General Questions and Answers / how to build the graphene nanoribbons?
« on: June 23, 2010, 04:35 »
Hi,
I want to build the graphene nanoribbons. So I download the graphene_ribbon.py file from the http://quantumwise.com. However, when I drug it into the VNL, It does not work. can anyone details the method of building the graphene nanoribbons? Thank you !

8
General Questions and Answers / how to build the silicon nano-wire?
« on: June 8, 2010, 09:47 »
hello,
I want to calculate the energy band of silicon nano-wire, but I don't know how to build it with VNL. Can any one show me the details? thank you! :)

9
General Questions and Answers / Re: How to set to make the iSCF converge?
« on: May 31, 2010, 03:15 »
Quote from: Nordland on May 30, 2010, 18:03
What version of the program are you running?
The version is vnl-2008-10.0.

10
General Questions and Answers / How to set to make the iSCF converge?
« on: May 30, 2010, 14:43 »
hello, everyone
The set I made for scf calculation are listed as follow:
the energyshift 50 meV, ElectronicTemperature 300 K, DM.MixingWeight 0.25, DM.NumberPulay 6, mesh Cutoff 240 Ry,MaxSCFIterations 500
but,  it can not converge for scf calculation.

Are there any other parameters to be set for convergence of DM scf calculation? please help me ! thank you ! the elements used in that calculation are C, B, P.


11
General Questions and Answers / can ATK calculate the optical characteristic?
« on: May 5, 2010, 06:39 »
Hello, every body!

I want to use the VNL to calculate the optical characteristic, but I don't know how use it! Does anybody show me the details? :)

12
General Questions and Answers / Re: how to build the doped single wall carbon nanotubes?
« on: April 29, 2010, 06:47 »
many thanks for helping me ! you are all kind people! :)

13
General Questions and Answers / Re: how to build the doped single wall carbon nanotubes?
« on: April 28, 2010, 15:14 »
thank you very much ! I will try it! :)

14
General Questions and Answers / Re: how to build the doped single wall carbon nanotubes?
« on: April 28, 2010, 13:53 »
thank you for replying, I know this way, but the question is that how can I build the supercell of doped carbon nanotubes. using the Nanotube grower only produce periodic cell of carbon nanotubes. how can I build the supercell of doped carbon nanotubes? I mean, building the non-preriodic doped carbon nanotubes with hundereds of atoms.

15
General Questions and Answers / how to build the doped single wall carbon nanotubes?
« on: April 28, 2010, 08:22 »
Hi, everbody,
 I want to build doped single wall carbon nanotubes using the VNL, but I don't know how to build it. anyone can show me the details? please help me! thank you! :)

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