Please correct your English.

Thank u Sbasish dutta for your suggestion.

Dear John Clarkson,                                                   

                                      Thanks for your reply, I used aggregated Au nano particles having different diameter, we studied SERS effect along with SPR changes with time variation (1- 10 days) these effect changes with size of particle it changes with respect to time. Now my doubt is spherical Au nano particles won't shows any SERS effect but after 10 days the Au nano particles changes shape and diameter and gives very good SERS effect.