Bimetal nanocylinder 2D simulation

I am trying to model the local electric field enhancment given in figure 6 (Ag sphere) of this comsol paper (attached).

I am getting a peak for local field enhancement. However, I am getting a very sharp peak whereas the peak given in the reference paper is broader.

I have attached the model I have created. Can somebody please go through the model and tell me whether I am doing something wrong? What changes can I make to my model to reproduce the results given in the reference paper?