Plasmonic properties of CuS nanocrystals and thin films

In this work, we focus on the thin film deposition of Copper Sulphide(CuS) Nanoparticles(NPs) using various deposition techniques and the surface topography and optical characterization of these films using reflection/transmission Ellipsometry. Both Multilayer and Monolayer depositions are successfully executed using specifically oriented methodologies like substrate functionalization, Electrophoresis, to achieve various film thickness which were measuring using Atomic Force Microscopy(AFM). We then solve the fresnel reflection equations using the Ellipsometry data to calculate the anisotropic permittivity of the films. Finally we look at some future directions that can be interesting including Non-linearity investigation, Photo-catalysis and Plasmoelectric effect. We are also trying to measure the photo-degradation effects using these Nanoparticles in IR wavelength. By depositing highly smooth and uniform films of different thickness, we excite surface plasmon polaritons(SPP) on these films. We then use simulations to model the same effect and find agreement.
We try to dope the CuS nanodisks with Zinc using chemical synthesis and we observe controllable tuning of the LSPR wavelength depending on reaction temperature. Hence, we have devised a method to chemically tune the LSPR in CuS nanodisks.
Next, we will fabricate thin films out of these doped nanodisks to observe the change in SPP.
We are also trying electro-optic modulation of Surface Plasmon Polaritons in CuS thin films. We have tried to make thin ion-gel films over CuS films and applied a voltage bias to electrically modulate the surface charge density on the interface. We observed change in SPR intensity however the response time is much slower than expected thus indicating another mechanism at play. We are still trying to understand this.
However, next, we will try to put Silica or Tantalum Pentoxide thin coating over CuS and apply voltage bias to try electro-plasma modulation.