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Messages - beauyy

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31
General Questions and Answers / Re: Optoelectronic device
« on: June 2, 2015, 11:24 »
Thanks for your reply.
     But I want to calculate the current response of electronic device to the illumination with different intensity and wavelength.

32
General Questions and Answers / Re: What does the color mean in ldos with isosurface type?
« on: May 22, 2015, 10:40 »
I am using VNL 2014.2 to show the ldos. The color map I am using is HSV type, the isovalue is set as 0.01. I have attached the LDOS as below. I still don't know what the color mean in LDOS with isosurface type. I can not find the color bar .

33
General Questions and Answers / Optoelectronic device
« on: May 22, 2015, 06:49 »
Dear sir,
      Can ATK be applied to calculate the performance of optoelectronic devices, for example,  photodetectors and photodiode and so on?

34
General Questions and Answers / Re: Gate-Drain curves of p-doped ZnSe
« on: May 21, 2015, 02:58 »
The calculation part and device part have been included in the .py file attached below. The k-point in calculation is 5*5*100. It is large enough for this calculation. And the size along A direction seems impossible to be reduced. Is there anything wrong in my calculation?

35
General Questions and Answers / Re: Gate-Drain curves of p-doped ZnSe
« on: May 20, 2015, 03:23 »
Dear sir,
    I have attached the device .py  below. The neuman boundary conditions is applied along B direction.
   Of course, I am willing to make the central region longer, but it is difficult to converge.
   And the bigger vacuum region is also make the device more difficult to converge. 

36
General Questions and Answers / Gate-Drain curves of p-doped ZnSe
« on: May 15, 2015, 10:05 »
Dear sir,
        I am calculating the gate-drain curves of ZnS devices doped with MoO3 molecule. All the calculation at different gate voltage is SCF converged. But the drain current does not monotonously decrease with the rise of gate voltage. Is there any errors in this calculation？All the currents are calculated from the device configuration at lower gate voltage.

     The .py is listed as following:
#read in the old configuration                                                                                   
device_configuration = nlread("F:/MoO3/gate-ZnS-MoO3-0.8V-b0.4V.nc",object_id='gID000')[0]                       
calculator = device_configuration.calculator()                                                                   
metallic_region0 = device_configuration.metallicRegions()[0]                                                     
                                                                                                                 
# Define gate_voltages                                                                                           
gate_voltage_list=numpy.linspace(0.6,0.6,1)*Volt                                                                 
                                                                                                                 
for gate_voltage in gate_voltage_list:                                                                           
    device_configuration.setMetallicRegions(                                                                     
        [metallic_region0(value = gate_voltage)] )                                                               
                                                                                                                 
    # make a copy of the calculator and attach it to the configuration                                           
    # restart from the previous scf state                                                                         
    device_configuration.setCalculator(calculator(),                                                             
         initial_state=device_configuration)                                                                     
    device_configuration.update()                                                                                 
    nlsave('F:/MoO3/gate-ZnS-MoO3-0.8V-b0.6V.nc', device_configuration)                                           
                                                                                                                 
    #Analysis                                                                                                     
    filename= 'F:/MoO3/gate-ZnS-MoO3-0.8V-b0.6V.nc'                                                               
    transmission_spectrum = TransmissionSpectrum(                                                                 
        configuration=device_configuration,                                                                       
        energies=numpy.linspace(-2,2,101)*eV,                                                                     
        kpoints=MonkhorstPackGrid(5,5),                                                                           
        energy_zero_parameter=AverageFermiLevel,                                                                 
        infinitesimal=1e-06*eV,                                                                                   
        self_energy_calculator=RecursionSelfEnergy(),                                                             
        )                                                                                                         
                                                                                                                 
    nlsave('F:/MoO3/gate-ZnS-MoO3-0.8V-b0.6V.nc', transmission_spectrum,object_id='trans'+str(gate_voltage))     
    nlprint(transmission_spectrum)                                                                               

The device configuration is attached.


                                                                                                                 
                                                                                                                 
                                                                                                                 

       

37
General Questions and Answers / Transport behavior of perovskites
« on: May 4, 2015, 04:29 »
Dear sir,
     Is it possible for ATK 2014.2 to calculate the transport behavior of all kinds of perovskites? Is the crystal lattice of perovskites too large to model a device? If it is possible, how to simulate the different doping degree in  perovskite lattice, for example,  Sr2.46La0.54Fe2O7-d  ?

 

38
General Questions and Answers / Re: What does the color mean in ldos with isosurface type?
« on: April 1, 2015, 05:05 »
Can anybody answer this question?

39
General Questions and Answers / What does the color mean in ldos with isosurface type?
« on: March 26, 2015, 02:47 »
I drew the ldos of some devices. Some of ldos is red, and some is blue. What are the differences between the red and blue colors?

40
General Questions and Answers / hard to converge in IV curves of black phosphorus with F4TCNQ
« on: February 6, 2015, 04:33 »
Dear sir,
  I am calculating the I-V curves of black phosphorus with F4TCNQ. The transmission calculation is converged under 0 V, however it is different to converge under other bias. What is the problem?
  ATK 11.8.2 cannot calculate the transmission of black phosphorus under bias > 1.0 V, however ATK 14.2 can do it. Is it a bug in ATK 11.8.2? How can solve this problem?
  I have attached the IV calculation .py document.

41
General Questions and Answers / Can ATK be used to calculate the hole transport behavior?
« on: February 2, 2015, 08:03 »
Dear sir,
    I am calculating the electronic properties of P-type materials. I find that ATK software is always used to explain the electron transport behavior. But in P-type material, conductivity is caused by hole transport. Can ATK software be used to explain the hole transport behavior? 

42
General Questions and Answers / Re: odd shape of current-gate voltage curves
« on: January 17, 2015, 02:42 »
I changed the boundary_conditions in the x-direction to PeriodicBoundaryCondition. The computed residual has reduced to the same order of magnitude of required residual, but still larger than it. Without the spatial region, the device is easy to converge. But when a spatial region is applied on the device, it is difficult to converge even if the computed residual is within the tolerable error range.                                     




43
General Questions and Answers / Re: odd shape of current-gate voltage curves
« on: January 15, 2015, 02:39 »
Thanks for your suggestions. I checked my calculation in transmission of black phosphorus. It shows difficult to converge. During calculation, there is a repeated warning
WARNING                                                                     
# The computed multigrid residual is greater than the required accuracy.     
# Computed residual :   2.53311e-007                                           
# Required accuracy :   1.00000e-012     
The device has been optimized with LDA.SZ basis set.
What is the problem with it and how to solve is ?                                     

44
General Questions and Answers / odd shape of current-gate voltage curves
« on: January 13, 2015, 01:48 »
Dear sir,
   I have drawn a current-gate voltage curve for black phosphorus at bias voltage= 0.5 V by using a python script, but the curve is odd. The current are SCF calculated  with LDA.SZ basis set. In most cases, the curves should be monotonic. What's the matter with my calculation? 


45
General Questions and Answers / effctive mass calculation in ATK 11.8.2
« on: December 25, 2014, 04:20 »
Dear sir,
    I am going to calculate the effective mass in MoS2 nanoribbon and have read the tutorials in http://www.quantumwise.com/publications/tutorials/item/500-effective-mass-of-electrons-in-silicon.
But in the ATK 11.8.2 that I am using, I can not find the effective mass calculation in custom analyzer.
   Would you please provide me the python script for calculating the effective mass in ATK 11.8.2?

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