QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: sathyajit on March 9, 2015, 09:37

Title: Calculating I-V of MoS2 transistor
Post by: sathyajit on March 9, 2015, 09:37

Hi,

I am trying to calculate the IV of MoS2 transistor. The script for the structure is mos2_transistor1.py and then I am running the script electrode_bias_loop.py to get the transmission spectrum for various drain source bias. Lastly i run the script selfconsistent_iv.py to get the IV curve. I used the modified scripts from the tutorial at
http://quantumwise.com/documents/tutorials/latest/GrapheneDevice/index.html/

Also I tried using doped and undoped electrode regions in the script mos2_transistor1.py.

Yet I am unable to get a reasonable IV curve(currents are of the order of 10^-30) and also the transmission spectrum is 0 within the source and drain chemical potential for most of the curves.
What could be possibly wrong ?

Regards
Sathyajit

Title: Re: Calculating I-V of MoS2 transistor
Post by: zh on March 9, 2015, 10:23

MoS2 is a semiconductor and it properties is quite different from that of graphene.

Title: Re: Calculating I-V of MoS2 transistor
Post by: sathyajit on March 9, 2015, 10:34

Thanks for the quick reply.
What changes do I need to make to my structure or calculations to simulate the transistor ?

Regards
Sathyajit

Title: Re: Calculating I-V of MoS2 transistor
Post by: sathyajit on March 11, 2015, 14:32

Can you please reply ?

Thanks
Sathyajit

Title: Re: Calculating I-V of MoS2 transistor
Post by: Anders Blom on March 11, 2015, 20:34

As noted by zh, MoS2 is a semiconductor with a fairly large band gap. You can't make a transistor from an insulator - even from intrinsic Silicon. You have to dope the structure to have some finite electron density in the conduction band.

Title: Re: Calculating I-V of MoS2 transistor
Post by: sathyajit on March 12, 2015, 12:45

Dr. Anders,

I have seen papers which report significant on current when MoS2 is undoped. (Ex. http://www.nature.com/nnano/journal/v6/n3/full/nnano.2010.279.html)
Please let me know the reason for doping the central region.

Regards
Sathyajit

Title: Re: Calculating I-V of MoS2 transistor
Post by: Anders Blom on March 12, 2015, 14:01

Sure, but their structure had metal contacts. Your contacts are semiconducting (MoS2) so you have no free carriers in the system.