Investigation on the Growth Process of Gold Nanoplates Formed by Seed Mediated Growth Method

Gold nanostructures have unique surface plasmon resonance (SPR) properties and it is widely used in photolectronic and sensing applications. In this study, gold nanostructures focusing on gold nanoplates have been fabricated on the quartz substrate using seed mediated growth method (SMGM). The SMGM consists of two processes which are seeding process and growth process. The effect of growth time during growth process on the formation of gold nanoplates on substrate surface was studied. The growth time was varied from 30 minutes to 18 hours to observe its density and optical properties on the substrate surface. The XRD analysis shows two peaks occurs at the plane (111) in position ∼ 38.2° and plane (200) at ∼ 44.3°. Through variation of the growth time, the optimum surface density is 93.5% with a total of 59.4% of the nanoplates shape from 5 hours growth time sample. The optical absorption spectrum of the sample shows two resonance peaks, ∼ 558 nm and 675 nm, which are corresponding to the transverse surface plasmon resonance (t-SPR) and the longitudinal surface plasmon resonance (l-SPR) respectively. Hence, it is found that the growth time affected the formation of the gold nanostructures. Longer growth period caused an increase in the formation of gold nanorods instead of gold nanoplates.