Preparation and characterization of a triple layered Au-PMMA-PbSe hybrid nanocomposite: Manipulation of PMMA spacer layer by oxygen plasma etching

A hybrid triple-layered nanocomposite structure of plasmonic gold (Au), polymethylmethacrylate (PMMA), and lead selenide (PbSe) quantum dot (QD) on quartz substrate was developed. The fabricated nanocomposite exhibited well-established triple-layered morphology (Au-PMMA-QD on quartz), but had different coupling distances between Au, on the bottom, and PbSe QD, on the top. Control of the coupling distances in terms of different thicknesses of a PMMA spacer layer was examined by etching for different durations, from 7 to 30 min. The corresponding thicknesses of the PMMA layer ranged from ∼3.8 to ∼88 nm at an etching rate of 2 nm/min. Atomic force microscopy measurements showed that the well-established triple-layered hybrid nanocomposite structure had the heights of ∼15 nm (Au) and ∼4 nm (PbSe QD). X-ray photoelectron spectroscopy results revealed the characteristic peaks assigned to each nanoparticle and polymer layer. The results illustrated the triple-layered structures with different PMMA spacer layers, with no cross interference between the layers.