QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: rebeda on October 25, 2019, 22:33

Title: Re: calculation of gate voltage Vs conductance for each bias voltages - reg.
Post by: rebeda on October 25, 2019, 22:33

Dear Sir,

Looking at the link below, I have successfully calculated conductance at different gate voltages.

https://docs.quantumwise.com/tutorials/graphene_nanoribbon_device/graphene_nanoribbon_device.html

How can I calculate the same for each of bias voltages (for 0.05 to 0.05 V(say))?
My aim is to draw coulomb diamond or conductance stability diagrams (2D contour plot) having V_g as the x-axis, V_b as y-axis and dI/dV as z-axis. Will you please help me.....  :(

Regards,
Rebeda

Title: Re: calculation of gate voltage Vs conductance for each bias voltages - reg.
Post by: Petr Khomyakov on October 28, 2019, 22:03

You can use IVCharacteristics study object for that, see https://docs.quantumatk.com/tutorials/ivcharacteristics/ivcharacteristics.html andhttps://docs.quantumatk.com/manual/Types/IVCharacteristics/IVCharacteristics.html. 

Title: Re: calculation of gate voltage Vs conductance for each bias voltages - reg.
Post by: rebeda on November 3, 2019, 12:02

Thank you..!!!!!

https://docs.quantumwise.com/tutorials/graphene_nanoribbon_device/graphene_nanoribbon_device.html

In the above link suggested by you,  they have calculated IV characteristics for one to two drain source voltages at a given range of gate source voltages. Can I calculate the same for a range of drain source voltages in a single script?(say from -0.1 to 0.1  Vds  step size be 0.02)

Regards,
Rebeda

Title: Re: calculation of gate voltage Vs conductance for each bias voltages - reg.
Post by: Petr Khomyakov on November 4, 2019, 09:42

But this is exactly what the study object does. It calculates the current for given V_ds and V_gs ranges, allowing to compute I-V_ds curves, as well as I-V_gs curves for a set of V_ds voltages in the given range, see also the manual for this study object, https://docs.quantumatk.com/manual/Types/IVCharacteristics/IVCharacteristics.html.  One just has to set the voltage ranges either in the GUI or script.

Within the study object, you can always add more points to the curves by adding more voltages  to the script and re-running it. The main feature of the study object is that it does not delete the previously-calculated data, but add newly-calculated set of points to the old data.

Title: Re: calculation of gate voltage Vs conductance for each bias voltages - reg.
Post by: rebeda on November 4, 2019, 11:12

In the script obtained from the link for IV characteristics analysis, I am not able to calculate the required results for the gate voltages and drain source voltages below

# Gate-source voltages
gate_source_voltages = numpy.linspace(-1.0, 1.0, 41)*Volt

# Drain-source voltages
drain_source_voltages = numpy.linspace(-0.05, 0.05, 11)*Volt

But,  it worked quite well when I calculated for two drain-source voltages, set as

# Gate-source voltages
gate_source_voltages = numpy.linspace(-1.0, 1.0, 41)*Volt

# Drain-source voltages
drain_source_voltages = numpy.linspace(-0.05, 0.05, 2)*Volt

I have attached my input script for your perusal.

Regards,
Rebeda

Title: Re: calculation of gate voltage Vs conductance for each bias voltages - reg.
Post by: Petr Khomyakov on November 4, 2019, 16:03

I am not sure I understand your issue. One can set a range of V_ds voltages and the number of V_ds voltages such that it will correspond to step dV_ds = 0.02 V. 

Title: Re: calculation of gate voltage Vs conductance for each bias voltages - reg.
Post by: rebeda on November 5, 2019, 08:23

The python scrip show error when i set the drain source voltages as below.

# Drain-source voltages
drain_source_voltages = numpy.linspace(-0.05, 0.05, 11)*Volt

will you please point out where did I go wrong...
Regards,
Rebeda

Title: Re: calculation of gate voltage Vs conductance for each bias voltages - reg.
Post by: Petr Khomyakov on November 5, 2019, 09:29

Please enclose the error message.

Title: Re: calculation of gate voltage Vs conductance for each bias voltages - reg.
Post by: rebeda on November 8, 2019, 18:28

Thank you so much for your reply!!!

I tried regenerating the error message for the third time, but to my surprise; it really worked!!!!!!

Will you please provide me the python script for calculating dI/dV from I-V data since I am not able to obtain dI/dV from the IV characteristics analyzer.

Regards,
Rebeda :D