QuantumATK Forum
QuantumATK => General Questions and Answers => Topic started by: sitangshu on January 10, 2012, 15:20
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Hi,
Thanks for your reply..... Can you provide me a script that will be universal to make a hydrogen passivation for nanowires of any element or compound?. For eg, if i want to make Si nanowire, i will put Si-H bond length to be 1.52nm. If i want to make Ge nanowire or InSb nanowire, I shall put Ge-H and InSb-H bond length to be some other values... etc., like that..........
In case, if you feel it gonna take more time to develop this script, can you please let me have H passivated Ge and InSb scripts?
Thanks in advance
Sitangshu
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Have a look at http://quantumwise.com/forum/index.php?topic=771.msg5744#msg5744
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Dear Dr. Blom,
I went through the script for Hydrogen passivation as mentioned in your link. However, it appears that it has been done for Si-H passivation. If I want to modify for Ge-H or some other xyz-H passivation a mere change in the bond length will do the job? Incidentally I tried using this logic, but the picture is not showing any H bond attached to Ge or other xyz compound.
please clarify this.......
thanks in advance
Sitangshu
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I fixed it up a little bit, just a few trivial details, like the Si-Si distance being hardcoded into the script. I tried it with a Ge nanowire; sometimes you have to change the nearest neighbor distance but now you can do that in the Customer Builder itself. This passivator works for both nanowires and molecules, but you have to choose that yourself, via the checkbox.
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Thank you very much Dr. Blom.........
This is an excellent help.
Regards
Sitangshu
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Dear Sir,
When I am going to passivate a nanowire structure of Ge, which is made by cleaving in builder tool, by using passivate_sp3.py, then it gives the following error
Traceback (most recent call last):
File "./zipdir/NL/GUI/Core/Runner.py", line 230, in run
File "<string>", line 32, in passivate
AttributeError: 'UnitCell' object has no attribute 'c'
but, if I will construct the nanowire in custom builder(nanowire), it does not give any error, Please help.
Regards
Ramkrishna
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The scripts for passivating are a bit "prototypes". In ATK 12.2 (coming out at least in a beta-version in a few days, hopefully), you will be able to passivate any structure, very easily.
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Dear Sir,
I am not able to passivate Ge, Si ( cleaved structure) by H using 12.2-beta-version builder just by clicking the H-passivation button. Can you please tell me the proper procedure to do that?
Regards
Ramkrishna
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Are you trying to make a nanowire? Did you add vacuum around? If the structure is still periodic, no H atoms will be added.
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Si should work, however Ge is actually not possible. Thanks for reporting it, it will be fixed for the final release.
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Yes, I am trying to make nanowire.
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So, here's the recipe, resulting in the picture attached.
1. Start Builder
2. Add Si from Database (see below about Ge)
3. Builders>Surface (Cleave), let's cleave it 100 and leave all parameters at default
4. Bulk Tools>Repeat, 10x10x1
5. Rotate the view so you see the XY plane. Try to align it as well you can to be perpendicular to the screen plane.
6. Now, with the mouse, draw a rectangle to select, say, a square of 10x10 atoms (you have 20x20 now). It doesn't really matter where you start, but from the corner is of course easier to count.
7. Here's the trick now: press Ctrl+I to invert the selection; then press Delete to remove all atoms except those we selected in 6.
8. Center the system in all directions via Coordinate Tools>Center.
9. Hit the Passivate button
Now, this forms your basic structure, for which you can compute the band structure, or from which you can construct a device.
If you want Ge instead, since the passivator has a small problem with this, what you do is select Ge form the Database (to get the correct lattice constant) but then change all atoms to Si temporarily. Perform all steps above, and at the end (after passivation) change back to Ge. To select all atoms of a particular element, hold down Shift while double-clicking with the left mouse button on an atom. Then you can use the "Periodic Table" button to change all selected atoms to a new element.
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Dear Sir,
Thank you so much for this recipe, its help me a lot to construct square [100] and [110] nanowire but still I am not able to construct a square (rectangular) [111] nanowire. Can you please help me for that?
Ragards
Ramkrishna
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The key for 111 is to note that the surface cell is hexagonal. Thus, to make a rectangular base for the wire, you need to convert the cell to an orthorhombic supercell. This is achieved by setting A'=2A+B and B'=B and C'=C. You can use the plugin "Bulk Tools>Supercell" to do this.