Problem on study gate effect onto MoS2 monolayer

[stclaireva]

 I am new to ATK. I am trying to reproduce the results from the paper: IEEE TRANSACTIONS ON ELECTRON DEVICES, 2013, 60, 2782. However, I cannot get the similar results.

The 'py' scripts I used are attached. First, I used 'mos2-hfo2-lad.py' to do device calculation and then calculate transmission spectrum with 'iv-anal.py'. With this procedure, I obtained IV curve with gate voltage fixed at 0V and  0.35 V (refer to the attached figure, please). The 0.35 V gate voltage supposes to greatly enhance the current. However, for my results, It seems the applied gate voltage has no effect on the current. Could you help check the script and device I build if there is something wrong?

I also tried the device with thinner (~10 angstrom) dielectric materials so that the gate can be placed closer to MoS2 monolayer. However, the gate voltage still gives little effect.

 I will appreciate if somebody can help.

[stclaireva]

Please, any idea!

[Anders Blom]

It would seem you are studying intrinsic MoS2 without doping. The article considers PMOS and NMOS.

[stclaireva]

It would seem you are studying intrinsic MoS2 without doping. The article considers PMOS and NMOS.

Thanks for your reply.
Yeah, you're right. But, as shown in the attached 'py' script, we also take the doping into consideration by setting up the charge state of electrode (charge=+/-0.01182). Such doping can ensure the  doping density ~10^20 /cm^3. (refer to the paper "We consider highly doped (10^20 /cm^3) n++ and p++ regions as the source/drain for the n-MOSFET and the p-MOSFET, respectively").

In the paper, they also mention they place MoS2 on the SiO2/Si substrate. Does this matter a lot? If it is, how to set it up in ATK?

[Anders Blom]

Only charging the electrodes will probably have a very small effect, you would also need to introduce the similar doping in the central region (it's unclear from the article if they did this in the reference or not).

I think you had better ask the authors of the article these details, also about the substrate - again it's unclear if this was done with atoms or just a dielectric region (although Fig. 1 tends to indicate they are all just spatial regions).

One might at this point take a moment and consider what kind of doping would be technologically possible to introduce in MoS2...