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QuantumATK => Questions and Answers => Topic started by: karma on January 9, 2018, 20:21

Title: photocurrent
Post by: karma on January 9, 2018, 20:21
how do we test the convergence for photocurrent calculation.
also is the bias volatge applied  to the left and right electrodes in the device calculator setting applicable during photocurrent analysis
Title: Re: How to calculate current density as a function of bias voltage
Post by: Wang Jin on May 23, 2019, 16:05
Dear all,
    1.  How to calculate current density as a function of bias voltage more easily? [PHYS. REV. APPLIED 10, 014026 (2018)]
   2.  How to calculate the transmission as a function of energy for the given photon? [Nano Letters 2018 18 (11), 7275-7281 ]

Thank you very much for your help.
Title: Re: photocurrent
Post by: Tue Gunst on June 4, 2019, 10:53
Convergence checks should be performed for the usual DFT settings.
When a good DFT simulation has been performed the kpoints and energies/energy_resolution used in the Photocurrent calculation should be checked.

A bias voltage is included in the usual way through the device calculator. Then one perform the calculation of the Photocurrent for each separate and converged device configuration at a given bias voltage.

The Photocurrent object has a query function "photocurrent.photonMediatedTransmission(photon_mode,...)" that can be used to obtain the transmissions as a function of energy for a selected photon energy index "photon_mode".
Please see the reference manual entry for Photocurrent for full description of the inputs to this query function:
https://docs.quantumwise.com/manual/Types/Photocurrent/Photocurrent.html#photocurrent-c
Title: Re: photocurrent
Post by: zhangguangping on July 19, 2021, 05:35
Convergence checks should be performed for the usual DFT settings.
When a good DFT simulation has been performed the kpoints and energies/energy_resolution used in the Photocurrent calculation should be checked.

A bias voltage is included in the usual way through the device calculator. Then one perform the calculation of the Photocurrent for each separate and converged device configuration at a given bias voltage.

The Photocurrent object has a query function "photocurrent.photonMediatedTransmission(photon_mode,...)" that can be used to obtain the transmissions as a function of energy for a selected photon energy index "photon_mode".
Please see the reference manual entry for Photocurrent for full description of the inputs to this query function:
https://docs.quantumwise.com/manual/Types/Photocurrent/Photocurrent.html#photocurrent-c


Dear Tue Gunst,

I also want to obtain the photon mediated transmission like that in Figure 6c of your paper [Nano Letters 2018 18 (11), 7275-7281]. However, when I use the following script in the .py input file, nothing obtianed except the photocurrent. Can you kindly give some help? thanks!

===
# -------------------------------------------------------------
# Analysis from File
# -------------------------------------------------------------
device_configuration = nlread('Au-Ben-Au-0.0.hdf5')[1]

# -------------------------------------------------------------
# Photocurrent
# -------------------------------------------------------------
kpoints = MonkhorstPackGrid()

photocurrent = Photocurrent(
    configuration=device_configuration,
    energies=numpy.linspace(-2, 2, 101)*eV,
    photon_energies=numpy.linspace(0, 5, 10)*eV,
    kpoints=kpoints,
    photon_polarization=[0+0j, 0+0j, 1+0j],
    energy_resolution=0.05*eV,
    calculate_all_transmissions=True,
    )
nlsave('Au-Ben-Au-0.0-PC.hdf5', photocurrent)

photocurrent.photonMediatedTransmission(photon_mode=0)

===
Title: Re: photocurrent
Post by: Tue Gunst on August 3, 2021, 10:45
The photon mediated transmission is not plotted in the gui but you can obtain the data from the object as you are suggesting.

energies = photocurrent.energies().inUnitsOf(eV)
transmission = photocurrent.photonMediatedTransmission(photon_mode=0)

and then plot these two variables with pylab or other prefered plotting tools (select wanted photon_mode index for which you want to plot the transmission).
Please see the object description here for further details:
https://docs.quantumatk.com/manual/Types/Photocurrent/Photocurrent.html#NL.Analysis.Photocurrent.Photocurrent
Title: Re: photocurrent
Post by: zhangguangping on August 3, 2021, 10:49
The photon mediated transmission is not plotted in the gui but you can obtain the data from the object as you are suggesting.

energies = photocurrent.energies().inUnitsOf(eV)
transmission = photocurrent.photonMediatedTransmission(photon_mode=0)

and then plot these two variables with pylab or other prefered plotting tools (select wanted photon_mode index for which you want to plot the transmission).
Please see the object description here for further details:
https://docs.quantumatk.com/manual/Types/Photocurrent/Photocurrent.html#NL.Analysis.Photocurrent.Photocurrent

Dear Tue Gunst´╝î

I now can get the photon mediated transmission.

Thanks very much for your kind reply.

With best regards,

/Guang-Ping Zhang