Author Topic: Schottky barrier and electrostatic potential convergence region  (Read 279 times)

0 Members and 1 Guest are viewing this topic.

qew394

• New QuantumATK user
• Posts: 3
• Country:
• Reputation: 0
Schottky barrier and electrostatic potential convergence region
« on: November 3, 2023, 17:00 »
Hello,

First of all, my system is device config of metal/amorphous semiconductor In-O (not metal/semiconductor/metal)

I tried to calculate the schottky barrier from LDOS.
I have read the tutorial and paper; ag-si interface  and Nanoscale Adv., 2021, 3, 567.

And I have found that the channel length must be long enough for the electrostatic potential to converge toward E=0

Here is my question. But what if  a channel of my system must have finite size like 2~3nm width?

My idea about this question is that it is impossible to simulate finite size of channel because  NEGF only works for open BC system. Am I correct..? If not, how to solve it.

AsifShah

• QuantumATK Guru
• Posts: 102
• Country:
• Reputation: 1
Re: Schottky barrier and electrostatic potential convergence region
« Reply #1 on: November 4, 2023, 16:19 »
Hi,

You mentioned "channel length" should be long enough for electrostatic potential (ESP) to converge to zero?

I think it is not the channel length but "electrode extensions" that should be long enough for ESP to converge to zero?

Correct me if I am missing anything!

Best Regards

qew394

• New QuantumATK user
• Posts: 3
• Country:
• Reputation: 0
Re: Schottky barrier and electrostatic potential convergence region
« Reply #2 on: November 5, 2023, 04:00 »
Thank you for the reply !

I might be wrong. But as I understood in the tutorial[1], it seems the semiconductor channel length must be long enough until the Hatree potential converge to the right electrode.

[1]https://docs.quantumatk.com/casestudies/ag_si_interface/ag_si_interface.html

AsifShah

• QuantumATK Guru
• Posts: 102
• Country:
• Reputation: 1
Re: Schottky barrier and electrostatic potential convergence region
« Reply #3 on: November 5, 2023, 08:39 »
Hi,
I think that is the previous version.
It should be an electrode extension.

May someone from QATK will respond properly.

Anders Blom

• QuantumATK Staff
• Supreme QuantumATK Wizard
• Posts: 5317
• Country:
• Reputation: 88
Re: Schottky barrier and electrostatic potential convergence region
« Reply #4 on: November 6, 2023, 21:42 »
It's the length of the entire device. With low doping this can be very long.

qew394

• New QuantumATK user
• Posts: 3
• Country:
• Reputation: 0
Re: Schottky barrier and electrostatic potential convergence region
« Reply #5 on: November 7, 2023, 12:19 »

My system doesn't need any doping. Then no need to make the system long ??
Although there is no doping, the gradient of electrostatic potential may occur near the interface, am I right??

Anders Blom

• QuantumATK Staff
• Supreme QuantumATK Wizard
• Posts: 5317
• Country:
• Reputation: 88
Re: Schottky barrier and electrostatic potential convergence region
« Reply #6 on: November 7, 2023, 18:59 »
I looked back at your original post. You need to separate two cases, which I think now are a bit mixed up. If you are looking for the Schottky barrier between two materials, then you would follow the approach as in our Ag/Si paper of the NiSi2 tutorial https://docs.quantumatk.com/tutorials/nisi2-si/nisi2-si.html. In both cases it is very helpful to introduce doping to screen the interface potential, but of course as we show in the paper, the barrier itself depends on this doping.

On the other hand, if you want to simulate a specific channel length, you just make the system the size you want, and add both left and right electrodes. In this case you still need to worry about the potential going flat but in metallic electrodes this happens very quickly. And again, if you use semiconducting electrodes, they need to be doped, how else would you get a current?