QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: Adila on July 29, 2015, 04:55

Title: IV of phosphorene FET
Post by: Adila on July 29, 2015, 04:55

Dear all,

I have simulated the IV curve for a phosphorene FET. As far as I understand, the IV curve was supposed to be an Id versus Vd graph. However, the trend of the graph was similar to the Id versus Vg graph.

Am I correct, or the graph was actually an Id versus Vg graph?

If I am correct, why was the trend similar to the Id versus Vg graph?

Here, I attached the python file and the IV plot.

Thank you in advance for your cooperation. I am really sorry for asking this question again.

Title: Re: IV of phosphorene FET
Post by: Umberto Martinez on August 6, 2015, 11:38

You do perform a source-drain voltage scan for a fix gate bias of 0.2 V.
For an example of a gate scan, see http://quantumwise.com/documents/tutorials/latest/NanowireDevice/index.html/chap.nanowiredevice.html#sect1.nanowiredevice.gatescan

results can be different of what you expects for a few reasons:
1- central region too short
2- electrodes too short, I would double them.
3- wrong k-points sampling. This is a 2D structure periodic in BZ plane. Use only 1 k-point along A direction. This applies to TS, Current density, and DDOS as well.
4- increase k-points along C. Default is 100.
5- use Naumann boundary conditions along A.

Title: Re: IV of phosphorene FET
Post by: Adila on August 9, 2015, 02:39

Dear Sir,

Thank you for your reply. I will try to simulate the structure according to your suggestions. Thank you so much.

Title: Re: IV of phosphorene FET
Post by: Adila on October 4, 2015, 09:55

Dear Sir,

I would like to confirm on the k-point sampling for phosphorene. Since my phosphorene is a two-dimensional, the k-point chosen should be in two directions. Is it correct if I put the setting like this?

Title: Re: IV of phosphorene FET
Post by: Anders Blom on October 4, 2015, 21:16

The question cannot be answered, as it depends on which directions (ABC) your 2D sheet spans.

Title: Re: IV of phosphorene FET
Post by: Adila on October 5, 2015, 05:01

Dear Sir,

Attached is my phosphorene FET. Is the k-point sampling above correct?

Title: Re: IV of phosphorene FET
Post by: Anders Blom on October 5, 2015, 10:06

It's appropriate. There is no such thing as "correct k-point sampling" and there is no guarantee your chosen numbers give accurate results, that needs to be tested.

Title: Re: IV of phosphorene FET
Post by: Adila on October 6, 2015, 03:51

Thank you very much Sir for your reply. I really appreciate it.