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Topics - 395235863

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16
General Questions and Answers / Bandstructure superposition
« on: March 21, 2016, 18:14 »
Dear QuantumWise Staff,

How to plot pic1(a)?

Are following steps right?
1.calculate the bandstructures of [MoS2 without contact] and [Au-MoS2 contact system] respectively
2.get the Fermi energy (Ef) of [MoS2 without contact] and [Au-MoS2 contact system] respectively
3. plot the bandstructure of  [Au-MoS2 contact system], Ef is the Fermi energy of [Au-MoS2 contact system]
4.plot the bandstructure of  [MoS2 without contact] and shift it by adding the difference in energy between the Fermi energy of[MoS2 without contact]and the Fermi energy of  [Au-MoS2 contact system]

Thank you very much!

17
General Questions and Answers / Why different boundary conditions get different fermi level?
« on: March 17, 2016, 15:12 »
Why different boundary conditions get different fermi level?
examples are given as pic.1

18
General Questions and Answers / Questions about InAs p-i-n junction tutorial
« on: March 8, 2016, 14:57 »
Dear QuantumWise Staff,
  I have read the tutorial (http://quantumwise.com/documents/tutorials/latest/InAsDevice/index.html/index.html).
  But how to get the VBM (0.02) in pic2 from pic1?
  In pic2 electron affinity (5.24 ) is different from the former one(5.085)(http://quantumwise.com/documents/tutorials/latest/InAsDevice/index.html/chap.nanowire.html#sect1.levels.eaff.left_ele)

Thank you very much!

19
General Questions and Answers / Why can't I use LDA with DFT-D?
« on: March 2, 2016, 11:09 »
Thank you in advance.

20
General Questions and Answers / Simulated current-voltage characteristics and extraction of n
« on: February 26, 2016, 08:54 »
Dear QuantumWise Staff,

  where can i get the orgin of the pic.Thank you!

21
General Questions and Answers / How to simulate FET's metal-semiconductor contact's Schottky barrier
« on: December 12, 2015, 09:20 »
Dear QuantumWise Staff :
  1.How to use a doping concentration range in device's electrode to simulate the experimental FET metal-semiconductor Schottky barrier ?How to choose the value of doping concentration?
  2.When i calculate device's Vgate-current curve, how do the dielectric thickness affect the current?Generally,in device simulation,should dielectric thickness be bigger than a critical value?
 
Thank you in advance.

22
General Questions and Answers / Projected Local Density of States
« on: November 27, 2015, 11:42 »
Dear QW team,
  I calculate the Projected Local Density of States.But I cannot export the data of PLDOS?Can you help me ? Thank you!

23
General Questions and Answers / mos2-fet
« on: November 20, 2015, 03:30 »
Dear QW team,
1.i-v curve must need DFT calculator,right?
2.i get mos2-fet i-v curve using DFT-GGA,but then i use DFT-GGA to calculate mos2 bandgap,the result is not good,then i get the following tutorial using CP2K DFTB
so i-v curve calculated before by DFT-GGA is reasonable? do i need to use CP2K DFTB set to calculate Mos2-fet i-v curve.
http://quantumwise.com/publications/tutorials/item/505-transmission-spectrum-of-perfect-sheets-of-graphene-and-mos2

Thank you!

24
General Questions and Answers / Chemical ,Effective, ExternPotential,Electrostatic Difference Potential
« on: October 28, 2015, 05:03 »
What are the differences among Chemical Potential, Effective Potential, External Potential, Electrostatic Difference Potential ?
Can you give examples for better understanding ?
Thank you !

25
General Questions and Answers / Boundary Conditions Set between two gate and one gate FET
« on: May 18, 2015, 16:15 »
i think there are three different two gate FET models in the following 3 pictures, as well as the single gate FET.
i want to know which model is suggested? can you tell me the differences among them in details?
after read http://quantumwise.com/forum/index.php?topic=1597.0
i don't know how to set B direction boundary conditions when i use two gate FET and single gate FET.like 1.png and 4.png
desired for your help
thank you !

26
Scripts, Tutorials and Applications / The computed multigrid residual is greater than the required accuracy
« on: May 17, 2015, 05:47 »
in the .e file
** Back Engine Exception : Singular value decomposition failed
** Location of Exception : mathutils.cpp:1604

in the log file
################################################################################
# WARNING                                                                      #
#                                                                              #
# The computed multigrid residual is greater than the required accuracy.       #
#                                                                              #
# Computed residual :         inf                                            #
# Required accuracy :   1.00000e-12                                            #
#                                                                              #
################################################################################

i attached the input.py out.log job.e files.

what the problems?

desired for your help!

thank you very much!

27
General Questions and Answers / some questions about ivcurve converge
« on: May 7, 2015, 11:03 »
1.There are two device models for semiconductor:

first,use Au(1,1,1)-semiconductor interface''http://quantumwise.com/documents/tutorials/latest/Au_Pentacene/index.html/index.html'';

second,use doping inATK''http://www.quantumwise.com/publications/tutorials/item/820-ni-silicide-si-interfaces''.

what the differences between the two-probe models?and which one is better to be converged?

2.There are two ways to calculate the iv curve:

first,use IVCurve and use biases = [0.0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0]*Volt;

second,use code in the web ''http://quantumwise.com/publications/tutorials/item/114-i-v-curve-and-voltage-drop'';

what the differences between the two ways?and which one is better to be converged?

and what the differences between biases = [0.0, 0.2, 0.4, 0.6, 0.8, 1.0] and biases = [0.0, 0.1, 0.2, 0.3, 0.4, 0.5,0.6,0.7,0.8,0.9,1.0]?is the latter one is converged better than the former one?

3.now i have studyed in 2D materials,i what to know what the range of  center region's length should be use so that the model can be converged better?

Thank you！

28
General Questions and Answers / The iv curve calculation did not converge to the requested tolerance!
« on: April 26, 2015, 04:16 »
when i  set max_steps=250 and i alse get the Warning
################################################################################
#                                                                              #
# Warning: The calculation did not converge to the requested tolerance!        #
#                                                                              #
################################################################################

now what can i do ?and i also want to know the maximum of  max_steps can be set

29
Installation and License Questions / License
« on: April 9, 2015, 09:49 »
i have 2 masters in license(2014).and now i  install  a 13.8 ATK(demo,14days for free)  in my cluster.
However，the 13.8 automatically use one of  masters in license(2014)

how can i get the solution? Thank you!

30
General Questions and Answers / piezoelectric
« on: March 17, 2015, 13:02 »
how to calculate piezoelectric in ATK?
Thank you!

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