Author Topic: MoS2 bandstructure  (Read 3227 times)

0 Members and 1 Guest are viewing this topic.

Offline naomi

  • Regular QuantumATK user
  • **
  • Posts: 16
  • Country: ir
  • Reputation: 0
    • View Profile
MoS2 bandstructure
« on: June 6, 2017, 17:17 »
Hey Dear,

It would be great if someone can help me to understand MoS2 bandstructure and the rest of 2D materials theory.
You are wondering what I am looking for? Well, we know Monolayer MoS2 is n-type So, how I got right bandgap value but p-type. ? if I am right n-type or p-type structure means  Ef located near conduction or valence band, but My graph shows Ef located in the middle.  why?
 
I used 1.1.1 to get MoS2 bandstructre. LDA-PZ
If you need extra information please let me know.


Thanks in advanced.

Offline Jess Wellendorff

  • QuantumATK Staff
  • Supreme QuantumATK Wizard
  • *****
  • Posts: 933
  • Country: dk
  • Reputation: 29
    • View Profile
Re: MoS2 bandstructure
« Reply #1 on: June 7, 2017, 08:14 »
In ATK, the Fermi level of an intrinsic semiconductor is nearly always positioned in the middle of the gap. There is no real physical insight to be gained from that fact. If you explicitly doped the semiconductor, you would see the Fermi level move up/down.

Offline naomi

  • Regular QuantumATK user
  • **
  • Posts: 16
  • Country: ir
  • Reputation: 0
    • View Profile
Re: MoS2 bandstructure
« Reply #2 on: June 7, 2017, 12:42 »
Dear Jess,

Thanks for your reply.
I have another question.  Pristine MoS2 is n-type, am I right? So If yes,  why I got p-type? :-(
 
If you look precisely into attached file you will see I have right bandgap but confused with n-type , p-type.
« Last Edit: June 7, 2017, 12:45 by naghmehtor »

Offline Petr Khomyakov

  • QuantumATK Staff
  • Supreme QuantumATK Wizard
  • *****
  • Posts: 1290
  • Country: dk
  • Reputation: 25
    • View Profile
Re: MoS2 bandstructure
« Reply #3 on: June 7, 2017, 13:57 »
I would guess that pristine MoS2 is an intrinsic semiconductor. It might be unintentionally doped in experiment, but you are doing simulations, so that we will need to dope it with electrons manually to have it n-type doped. Otherwise, it is assumed to be intrinsic by default.