Dear Rens Horst , actually SERS on gold adhered to quartz substrate is possible. May be the particular SERS design of the paper you are reading causes such a strong damping that signal enhancement is low or zero, but as clearly stated in the following paper:

https://www.osapublishing.org/ome/fulltext.cfm?uri=ome-7-1-73&id=355805

the damping effect would be bigger when the Ti adhesion layer is thicker, for a constant Au thickness of 15nm.

Decreasing the Ti thickness or/and increasing the Au thickness would reduce the damping effect.

As the gold thickness increases, the gold structure will feel less and less the effect of the Ti layer.

Hope it helps.

Dear Dr. Gómez and Durrani,

Thank you very much for the input.

If I understand it correctly I can suppress the damping effect by having a thicker gold layer on top of the Ti adhesion layer? (Or by having a thinner Ti layer, but this is not an option for me unfortunately).

Cheers,

Rens

Hi Rens,

Actually the damping effect will remain but just on the interface of Ti-Au and regions of gold close to this interface. However, on the top part of the Au layer the effect of damping will be minimal or just null if the thickness is enough.

According to the article by Debu et al. 15nm Au could be enough if the Ti layer is thin enough (2nm), but 15nm is actually a very thin film, often SERS substrates both commercial and experimental have thicker layers (take by example Karite substrates, they have a 300nm Au coat).

I have coated glass and quartz with gold without using Ti or anyother adhesion layer and the gold adhesion was fairly good.

Good luck with your experiments!

Hey Manuel,

I checked my Au layers and they are roughly 150 nm thick on top of a ~10 nm thick Ti layer. I unfortunately have no control over the coating process as we bought these substrates. If I understand it correctly, the damping will mostly occur near the Ti-Au interface, so any plasmon resonance on my Au-surface should stay relatively undamped?

Hi Rens,

150 nm of Au should be more than enough to avoid the damping caused by the Ti layer if your SERS experiments are performed on the top of the substrates... It would be hard to place your molecules into the interface between Au and Ti :).

Bear in mind that commercial substrates could have a "nominal" Au thickness because of their nanostructured characteristics.

Hey Manuel, that is good to hear!

Thanks for the input. I will definitely give it a try.

Cheers,

Rens