Messages

1

General Questions and Answers / Strain on CNT

« on: September 28, 2014, 12:24 »

Hi, What is the method For apply uniaxial strain on CNT...!!!???

2

General Questions and Answers / Re: Si Nanowire

« on: August 14, 2014, 14:43 »

OK, Thanks ...
I've done all the steps are similar for created Gaas Nanowire but several questions ...!!!???
1. passivated [100] Gaas Nanowire (1X1 nm^2 cross-sectional area) Was performed as follows, do you think it is correct ...!!!???

I don't understand why you ask such question so many times. Once you understand the basic procedure (and steps), you can judge it by yourself.

Maybe the calculated band gap is too small. You can zoom in the plot to show the energy range around  0.0 eV (e.g. -0.5 eV to  0.5 eV). In such small energy range, you may see the band gap.  If not, you had better calculate the bulk material using the same key parameters ( pseudopotential, exchange-correlation functional, and mesh cutoff) to check the band gap of bulk material at first. And so you should ensure that all surface atoms are passiviated by hydrogen and that the structure is optimized.
 

My basic problem It is, I can not apply passiviated by hydrogen on gallium atoms, How I can passiviated the gallium atoms ...!!!???
http://upload7.ir/imgs/2014-08/00526715511832186959.jpg

............................................................................................

I'm trying to created a square cross sectional area for [111]Silicon Nanowire by Changes in values surface energies but still I could not do this work, Is it possible to do this ...!!!???

3

General Questions and Answers / Re: Si Nanowire

« on: August 13, 2014, 22:27 »

OK, Thanks ...
I've done all the steps are similar for created Gaas Nanowire but several questions ...!!!???
1. passivated [100] Gaas Nanowire (1X1 nm^2 cross-sectional area) Was performed as follows, do you think it is correct ...!!!???

http://upload7.ir/imgs/2014-08/51853168370542971296.jpg
http://upload7.ir/imgs/2014-08/07580765174953827058.jpg

2. I've used DFT (GGA) method for Calculation Eg but The value is not visible ...!!!???

http://upload7.ir/imgs/2014-08/99279190190848496906.jpg

4

General Questions and Answers / Re: Si Nanowire

« on: August 13, 2014, 07:16 »

Thank you for Reply to my question But two Questions ...!!!
1. How I can build a circular cross section ...!!!???
2. Can I use from method Created Silicon Nanowire for created Gaas Nanowire ...!!!???

Thanks

5

General Questions and Answers / Re: Si Nanowire

« on: August 9, 2014, 19:13 »

It is quite unreasonable to adjust manually (e.g., manipulate the atoms by the mouse or by shifting their coordinates in the input file) the distance between atoms. Before calculating the electronic structures (e.g, band structure and effective mass) of a nanowire built from the tool, one has better do the geometry optimization for the positions of atoms for the unstrained and strained nanowires.   

The steps in the basic procedure for your calculations seem OK.

When I'm using the method Extended Huckel, This geometry optimization is disabled ...!!!
http://www.upload7.ir/imgs/2014-08/84806232974711050359.jpg

My next problem is that, the results that I got the results of different article ...!!!
Eg For:
          1 nm ---> 2.514
          2 nm ---> 1.825
          3 nm ---> 1.532

But the results of article :
http://img.majidonline.com/pic/309058/01.png

................................................................

My next question, Can I use the following settings for apply biaxial strain ...!!!???
http://www.upload7.ir/imgs/2014-08/09143309982231980892.jpg

...............................................................

My last question, How do I calculate the effective mass (transport and subband) to SiNW (Of course using the training)...!!!???
http://quantumwise.com/publications/tutorials/mini-tutorials/135
 
...............................................................

Please, Can you help me ...!!!???, I am impatiently waiting for your answer ...

6

General Questions and Answers / Re: Si Nanowire

« on: August 8, 2014, 19:54 »

How can apply very low distance between atoms (for example Si-Si = 0.24 nm) ...!!!???
Is there any way for zoom in on very low distance between atoms ...!!!???
 

Sometimes it is difficult to capture the exact points in your question because of the grammar.

The distances between atoms in a system you have built are coherent, that is to say, they depend on how you build a system. For example, if you build a Si nanowire with a length longer than 0.24 nm, you can find some of atoms being equal to or larger than 0.24nm, otherwise, in a Si nanowire with a length shorter than 0.24nm you cannot find any two atoms with distance larger 0.24nm.

For the appearance of two atoms with long distance  on the screen during the zooming in process, it somehow depends on the screen size of your computer.  For a smaller screen size, such two atoms could be out of the screen when they are zoomed in.

I'm reading this article and done all settings are according to the article, just I could not adjust the distance between atoms ...

http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6178787

http://upload7.ir/imgs/2014-08/27814446166383853560.jpg

Do you think I've done it correctly simulation of SiNW ...!!!???, I am impatiently waiting for your answer ...

7

General Questions and Answers / Re: Si Nanowire

« on: August 6, 2014, 20:44 »

How can apply very low distance between atoms (for example Si-Si = 0.24 nm) ...!!!???
Is there any way for zoom in on very low distance between atoms ...!!!???
 

8

General Questions and Answers / Re: Si Nanowire

« on: August 4, 2014, 21:27 »

Thank you very much, but is it possible that the tutorial a little earlier this ...!!!???, My time is very limited ...!!!???

9

General Questions and Answers / Re: Si Nanowire

« on: August 3, 2014, 18:02 »

Based on this Topic :
http://quantumwise.com/forum/index.php?topic=1052.0#.U95Tnr_wnj4

http://www.upload7.ir/imgs/2014-08/92265838961736186181.jpg
http://www.upload7.ir/imgs/2014-08/93203916252802981644.jpg
http://www.upload7.ir/imgs/2014-08/40427145360407554157.jpg
http://www.upload7.ir/imgs/2014-08/61577216854170155155.jpg

for created and Simulation [100] Si Nanowire (1.5X1.5 nm^2 cross-sectional area), I have done the following steps:

for created [100] Si Nanowire :

http://upload7.ir/imgs/2014-08/64394798068228741408.jpg
http://upload7.ir/imgs/2014-08/41156585695590955640.jpg
http://upload7.ir/imgs/2014-08/44296824178491580621.jpg

for passivated [100] Si Nanowire :

http://www.upload7.ir/imgs/2014-08/29105611932879888547.jpg
http://www.upload7.ir/imgs/2014-08/14588447352801611893.jpg

Lattice Parameters :

http://www.upload7.ir/imgs/2014-08/67961499768988867807.jpg

for Calculator Eg and effective mass to [100] Si Nanowire :

http://www.upload7.ir/imgs/2014-08/66775900918855671719.jpg
http://www.upload7.ir/imgs/2014-08/48782454675948906868.jpg
http://www.upload7.ir/imgs/2014-08/16368757109887140695.jpg
http://www.upload7.ir/imgs/2014-08/17943543256305237287.jpg
http://www.upload7.ir/imgs/2014-08/12171100825222868728.jpg
http://www.upload7.ir/imgs/2014-08/40572682809530760451.jpg
http://www.upload7.ir/imgs/2014-08/52517970968663579648.jpg
http://www.upload7.ir/imgs/2014-08/61405080939064703739.jpg

Results :

http://www.upload7.ir/imgs/2014-08/28941439725807153255.jpg
http://www.upload7.ir/imgs/2014-08/83147039131564889848.jpg
http://www.upload7.ir/imgs/2014-08/05488740744683770722.jpg
http://www.upload7.ir/imgs/2014-08/74994397913592353034.jpg
Eg=1.981, K[0,0,0]

for apply Strain to [100] Silicon Nanowire (Uniaxial Tensile Strain 1%): 5.4306--->5.5306

http://www.upload7.ir/imgs/2014-08/77792845580931293334.jpg

I have done the correct steps ...!!!???, How  I can calculated effective mass (transport and subband) to [100] SiNW ...!!!???
Please help me  

10

General Questions and Answers / Re: Si Nanowire

« on: July 31, 2014, 13:14 »

Thank you for Reply to my question But Several Questions ...!!!???

......................................................................

How can to this method specify the dimensions of SiNW ...!!!???
For example, cross sectional:
1 × 1 nm^2 , 2 × 2 nm^2 , 3 × 3 nm^2 , 4 × 4 nm^2 or ...

......................................................................

How can apply strain (tensile , compressive) to in method ...!!!???
For example, apply tensile strain : 1% or 0.5%

......................................................................

for study Changes Eg as function of Changes dimensions of the cross section to SiNW, Necessarily use from tight binding method ...!!!???

......................................................................

Can we use from This Tutorial for calculated effective mass (transport and subband) to SiNW...!!!???
http://quantumwise.com/publications/tutorials/mini-tutorials/135

11

General Questions and Answers / Re: Si Nanowire

« on: July 29, 2014, 17:31 »

For study the effects apply Strain and study the effects Changes Thickness, I created Structure Silicon Nanowire by This Tutorial (Of course to page 11)

http://quantumwise.com/documents/tutorials/latest/NanowireDevice/NanowireDevice.pdf
http://quantumwise.com/documents/tutorials/latest/NanowireDevice/index.html/

......................................................................

A Question, Is it this structure is correct...!!!???

http://upload7.ir/imgs/2014-07/13180241540132818159.jpg
http://upload7.ir/imgs/2014-07/83418215152143289239.jpg
http://upload7.ir/imgs/2014-07/69019438953797660762.jpg
......................................................................

If correct structure, My next question relates to the definition dimensions of Cross section, Is it possible to change the distance between the atoms for create cross sectional 1 × 1 nm^2
http://www.upload7.ir/imgs/2014-07/89183462491135673753.jpg

The amount of default ATK to Tutorial is 170 × 170 nm^2
http://www.upload7.ir/imgs/2014-07/78322766137336276152.jpg
......................................................................

My next question, How can calculation Eg of silicon nanowire By metod tight binding ...!!!???


Thanks

12

General Questions and Answers / Re: Si Nanowire

« on: July 28, 2014, 17:30 »

Thank you for reply to my question But My basic question is related to dimensions of the cross section To Silicon Nanowire for Simulation By ATK, Is there a method for apply dimensions Based on nm (Nano Meter) ...!!!???
My next question related to exhibition Schematic By ATK, Is there a method for exhibit Changes Eg as function of Changes dimensions of the cross section Based on graphical figure ...!!!???
For example :
http://img.majidonline.com/pic/309058/01.png
exhibition graphical Changes Eg as function of Changes dimensions of the cross section (Axis X = Changes dimensions of the cross section , Axis Y = Changes Eg)
Thanks

13

General Questions and Answers / Si Nanowire

« on: July 27, 2014, 14:00 »

Hi, Is there a method for apply the dimensions of the cross section Based nm ...!!!???
For example :
[100] Silicon Nanowire (square cross section 1.5 × 1.5 nm^2)

......................................................................

My next question, Is there a method for exhibit (Eg OR effective masses) as function of Changes dimensions of the cross section OR apply Strain ...!!!???

http://img.majidonline.com/pic/309058/01.png
http://img.majidonline.com/pic/309059/02.png
http://img.majidonline.com/pic/309060/03.png

References:
http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6178787
http://www.sciencedirect.com/science/article/pii/S0038110112003516

......................................................................

Thanks

14

General Questions and Answers / Re: strain on Si

« on: July 26, 2014, 16:41 »

Thanks, A Question ...!!!
How apply uniaxial strain to Nanowire By ATK ...!!!???
Is it possible to use the option Builders --->Interface ...!!!???

15

General Questions and Answers / Re: strain on Si

« on: July 26, 2014, 12:14 »

Hi, What is the method For apply strain (uniaxial and biaxial) To Silicon Nanowire [100] [110]...!!!???