Si Nanowire

[zh]

1. please refer to the discussion in the following thread:
http://quantumwise.com/forum/index.php?topic=2026.0

2. the reasons for your results different from those reported in literature could be quite complicated, e.g., even the thickness of nanowires are the same as those in literature, the atomic positions and the computational setup (e.g., some key parameters in the computational method) may be different.  To reproduce the results in literature, it usually needs more patients and carefulness. Sometimes it is necessary to contact the authors of the original sources in order to figure out the exact reasons, because more or less details of computational setup were hidden in paper.

3. As said last several posts, you cannot apply  biaxial strain to an individual nanowire.  The manner illustrated in your image is not applicable because the lattice constant A includes the vacuum thickness. The change in the lattice constant A is just  to alter the vacuum thickness. 

4. Yes, the effective mass of a nanowire can obtained by following that tutorial.

[Black Metal]

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

[zh]

1. The nanowire with circular cross section could be built by choosing proper values for the surface energies [100], [110], [111]. Please try different values by yourself to find out the proper ones. Please don't ask the exact values.

2. Using the similar steps you of course can build the GaAs nanowire from cubic bulk GaAs.

[Black Metal]

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

[zh]

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.
 

[Black Metal]

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 ...!!!???

[Anders Blom]

There is a new way to passivate e.g. III-V structure coming out in VNL 2014, and there is an accompanying tutorial for it, which will come online next week.