31
General Questions and Answers / Bloch-state velocity
« on: March 11, 2017, 14:54 »
Hi
Is the Bloch-state velocity in ATK same as Fermi velocity?
Thanks.
Is the Bloch-state velocity in ATK same as Fermi velocity?
Thanks.
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32
General Questions and Answers / How to build phosphorene nanoribbons?
« on: October 29, 2016, 09:37 »
Hello
I can easily build any graphene nanoribbon in VNL. However I'm trying to build armchair and zigzag black phosphorene nanoribbons and couldn't accomplish since some atoms have translation as shown in the attached figure. I'd be glad if you could help me build these structures. Thanks.
I can easily build any graphene nanoribbon in VNL. However I'm trying to build armchair and zigzag black phosphorene nanoribbons and couldn't accomplish since some atoms have translation as shown in the attached figure. I'd be glad if you could help me build these structures. Thanks.
33
General Questions and Answers / How to obtain dihydrogenated GNR?
« on: November 17, 2015, 20:54 »
Hello
I can easily form GNR with mono hydrogen at the edges with VNL nanoribbon builder. How can I get a GNR with double hydrogen at the edges? Thanks.
I can easily form GNR with mono hydrogen at the edges with VNL nanoribbon builder. How can I get a GNR with double hydrogen at the edges? Thanks.
34
General Questions and Answers / q-points for inelastic transmission spectrum calculation of nanoribbons
« on: November 7, 2015, 15:46 »
Hello,
I replicated the silicon pn junction inelastic transmission spectrum tutorial. For the silicon structure, following q-points are used in the tutorial:
However I couldn't figure out what Q points to use when I try to find the ITS of nanoribbon structures.
Your help would be appreciated.
Kindest regards
Narin
I replicated the silicon pn junction inelastic transmission spectrum tutorial. For the silicon structure, following q-points are used in the tutorial:
Code
# Define q-points; take only points in first quadrant in (qx,qy) space
numQx = 7
numQy = 7
dQx = 0.5
dQy = 0.5
qx = numpy.linspace(0,dQx,numQx)
qy = numpy.linspace(0,dQy,numQy)However I couldn't figure out what Q points to use when I try to find the ITS of nanoribbon structures.
Your help would be appreciated.
Kindest regards
Narin
35
General Questions and Answers / Re: Something's wrong in the transmission spectrum of silicon pn junction tutorial
« on: October 31, 2015, 11:38 »
Hi,
Thank you very much for your reply. Here's the Iv curve with additional plots:
Also, DDOS at 0V, -1V and 1V biases are as follows consequently:
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IMO, the DDOS images have no similarity with the DDOS images of the silicon pn junction tutorial. Also not compilant with the DOS of a pn junction given in http://wanda.fiu.edu/teaching/courses/Modern_lab_manual/pn_junction.html referenced in the tutorial. Is it the screening length or the doping error, how can I obtain a proper pn junction with soped GNR in ATK, your help would be very much appreciated. Regards.
Thank you very much for your reply. Here's the Iv curve with additional plots:
Also, DDOS at 0V, -1V and 1V biases are as follows consequently:
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bilder uploaden
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IMO, the DDOS images have no similarity with the DDOS images of the silicon pn junction tutorial. Also not compilant with the DOS of a pn junction given in http://wanda.fiu.edu/teaching/courses/Modern_lab_manual/pn_junction.html referenced in the tutorial. Is it the screening length or the doping error, how can I obtain a proper pn junction with soped GNR in ATK, your help would be very much appreciated. Regards.
36
General Questions and Answers / Re: Something's wrong in the transmission spectrum of silicon pn junction tutorial
« on: October 29, 2015, 18:37 »
Thank you for your replies. I got it now. And a connected question (may be a recurring question) is that when I do the doping same as the silicon pn junction in a graphene nanoribbon pn junction (as attached) where left is p-doping and right hand side is n-doping, the current-voltage relationship is like this:
I couldn't solve why it is the origin symmetric of the silicon pn characteristics. When the junction is p-n, p side is anode and n side is cathode and the current should be as in the silicon pn junction. I coulnd't figure this out for 2 weeks. Your kind help is appreciated. Best regards.
I couldn't solve why it is the origin symmetric of the silicon pn characteristics. When the junction is p-n, p side is anode and n side is cathode and the current should be as in the silicon pn junction. I coulnd't figure this out for 2 weeks. Your kind help is appreciated. Best regards.
37
General Questions and Answers / Something's wrong in the transmission spectrum of silicon pn junction tutorial
« on: October 29, 2015, 16:36 »
Hi,
I did the silicon pn junction tutorial (http://quantumwise.com/publications/tutorials/item/828-silicon-p-n-junction) exactly as stated. When I inspect the transmission from the I-V curve object there seems something weird. In the V=-1V bias, the transmission looks like this:
The transmission is reported as 4.88E-16 in the bias window. At V=1V bias, where pn junction is conducting, the transmission spectrum is this:
.
The transmission at V=1V bias is reported as 3.61E-23 in the bias window.
The current calculation is this:
The current at V=-1V is zero while at V=1V bias, there's the forward current of 0.9nA. According to the transmissions, current of V=-1V should be higher than the current at V=1V. Why is there a contradiction here like this? I ask for your kind help. Thanks in advance.
I did the silicon pn junction tutorial (http://quantumwise.com/publications/tutorials/item/828-silicon-p-n-junction) exactly as stated. When I inspect the transmission from the I-V curve object there seems something weird. In the V=-1V bias, the transmission looks like this:
The transmission is reported as 4.88E-16 in the bias window. At V=1V bias, where pn junction is conducting, the transmission spectrum is this:
. The transmission at V=1V bias is reported as 3.61E-23 in the bias window.
The current calculation is this:
The current at V=-1V is zero while at V=1V bias, there's the forward current of 0.9nA. According to the transmissions, current of V=-1V should be higher than the current at V=1V. Why is there a contradiction here like this? I ask for your kind help. Thanks in advance.
38
General Questions and Answers / Re: The meaning of the current in Z direction
« on: October 21, 2015, 09:04 »
Hi Mr. Blom,
There is also a similar problem with my IV curve of the doped GNR simulation. http://quantumwise.com/forum/index.php?topic=3682.0
The IV curve seems the opposite direction, so I guess current flows in z- direction when the applied voltage is positive. Is there a way to correct it in ATK?
Thanks.
There is also a similar problem with my IV curve of the doped GNR simulation. http://quantumwise.com/forum/index.php?topic=3682.0
The IV curve seems the opposite direction, so I guess current flows in z- direction when the applied voltage is positive. Is there a way to correct it in ATK?
Thanks.
39
General Questions and Answers / Re: IV curve of a doped GNR
« on: October 15, 2015, 13:29 »
Hi,
Thanks for your help. Regards.
Thanks for your help. Regards.
40
General Questions and Answers / Re: IV curve of a doped GNR
« on: October 14, 2015, 15:16 »
Hi
Thanks for your replies. I'm comparing the IV curve of the silicon pn junction tutorial http://quantumwise.com/publications/tutorials/item/828-silicon-p-n-junction and the IV curve given in that tutorial:
My IV curve seems to have currents in the opposite way, in negative voltages the current flows but in the tutorial in positive voltage current flows, I'm using the same doping direction as can be seen from my code and the tutorial.
And your first question: I checked the log file and the calculations have converged.
Thanks a lot.
Thanks for your replies. I'm comparing the IV curve of the silicon pn junction tutorial http://quantumwise.com/publications/tutorials/item/828-silicon-p-n-junction and the IV curve given in that tutorial:
My IV curve seems to have currents in the opposite way, in negative voltages the current flows but in the tutorial in positive voltage current flows, I'm using the same doping direction as can be seen from my code and the tutorial.
And your first question: I checked the log file and the calculations have converged.
Thanks a lot.
41
General Questions and Answers / IV curve of a doped GNR
« on: October 13, 2015, 20:26 »
Hello
I tried the simulation of a doped armchair GNR (N=10) and obtained its IV curve, I attached my script. I did the doping exactly the same direction as the silicon pn junction tutorial. However as you can see from the attached nc file (https://dropmefiles.com/lRHvy), IV curve is inversed. Could you please give an idea on why I got an inversed IV curve. Also, there are ripples in the non-conducting regime as you can see. Is it normal or should I fine adjuct any parameters? Thanks a lot. Regards.
I tried the simulation of a doped armchair GNR (N=10) and obtained its IV curve, I attached my script. I did the doping exactly the same direction as the silicon pn junction tutorial. However as you can see from the attached nc file (https://dropmefiles.com/lRHvy), IV curve is inversed. Could you please give an idea on why I got an inversed IV curve. Also, there are ripples in the non-conducting regime as you can see. Is it normal or should I fine adjuct any parameters? Thanks a lot. Regards.