DOS of MoS2/Au interpretation

[Manish95]

I did a DOS calculation of monolayer MoS2/Au system with thick vacuum (35 Ang) on the c direction. I got DOS like the one shown in figure. But in the band gap region, I don't get any region with 0 DOS for MoS2/Au system. My structure also does not seem like it has been optimized (not much change in position of Au atoms) although the geometry optimization showed that the structure has been optimized.

My question is, if I give the vacuum region too much, is it going to affect my calculations? And if yes, then why? I suppose if larger the vaccum, the better it is for Veff to decay smoothly.

[Petr Khomyakov]

But in the band gap region, I don't get any region with 0 DOS for MoS2/Au system.

In the hybrid system, there should be no gap, because Au is metal, meaning that there is no energy gap. 

My question is, if I give the vacuum region too much, is it going to affect my calculations?

The results should be converged with respect to vacuum thickness. At some point, they must virtually not change upon increasing the vacuum region.