PVP-assisted thermal annealing of thin Au layer for creation of effective and reproducible SERS substrates

Abstract

Creation of SERS substrate with the large active area and homogeneous distribution of hot spots is now one of the most important tasks in the field of SERS practical implementation. This problem has been solved by various techniques, but the most applicable of them are expensive due to highly technical nature. In this work, a simple alternative approach based on thermal annealing of sputtered Au layer has been proposed. Usually, the thermal annealing of the thin Au layer leads to the formation of gold clusters array with high plasmon efficiency but with too wide size distribution and highly disordered arrangement. To overcome this drawback the previous soaking of Au layer in the poly(vinylpyrrolidone) (PVP) solution was proposed, with the aim to affect clusters formation and achieve the more homogeneous distribution of created hot spots array. Annealed Au and Au-PVP thin layers were characterized by AFM, XRD, XPS, UV–Vis and Raman spectroscopy techniques. Present results indicate that the PVP treatment before thermal treatment significantly affect the growth of the clusters and provide the perspective way for increasing of SERS efficiency and reproducibility.