Question about Heterojunction

[hieido]

I have a question about how to create a hetero-junction with 2 layer.
I have idea about new device, It looks like this: Gold layer/ Silicon layer (maybe be passivated by Hydro)  then Molecules with the absence of Sulfur/Silicon layer(passivated by hydro)/ Gold layer.
I thinks it gone be fun. But how to make this device? I used the bulk nano wire to build just [AU-Si/molecules/Si-Au] then optimization this one but the optimization take a long time and there were some errors.
So confusing~ can anybody help me~

[zh]

The most important points:
1) prepare a properly initial structure for Silicon layer (maybe be passivated by Hydro), i.e., silicene;
2) choose a proper size for gold layer and also for the silicon layer to ensure them be matched well as possible.

[hieido]

Thank for your reply,
I tried to create this device by following your advice,
First, I created the simple one just Au/Si/molecule/Si/Au and then optimization. But it take a long time.
In optimization condition: I choose MAX force: 0.5, MAX step 300, Step size:1 and the electron temperature 1600K
and both Si, Au is single zeta polar
But I have a question:
how can I get the result as soon as possible?
after optimization, is this real structure?
Can I calculation electron transfer of this kind of device?