Electrodeposition of CdSe Films: In-Situ Study by Spectroscopic Ellipsometry

Abstract

In-situ spectroscopic ellipsometry / CdSe film / Electrodeposition / Optical constantsCdSe films grown on Ti-coated polished steel by constant-current deposition from an aqueous solution containing selenosulfite and cadmium nitrilotriacetate have been studied by spectroscopic ellipsometry under in-situ conditions. Ellipsometric parameters, tanΨ and cos∆, were measured both as a function of deposition time at λ ϭ 825 nm and of wavelength (λ ϭ 500Ϫ900 nm) for constant film thickness from 0.02 µm to 2.3 µm. The model used for data analysis, Ti-substrate | TiO 2 | CdSe-film | solution, with optically homogeneous phases was valid for film thickness larger than 0.3 µm. Refractive indices and extinction coefficients of the 2.3-µm film were derived for λ ϭ 500Ϫ900 nm. A direct band-gap of 1.72 eV was determined. The faradaic efficiency of electrodeposition was 0.93 for a current density of 50 µA cm Ϫ2 .

Planar Polarized Light Emission from CdSe Nanoparticle Clusters

“…The enhanced planar waveguiding properties of the clusters are likely related to the structural and compositional characteristics of these materials. First, the refractive indices of Ca 2 Nb 3 O 10 (2.49 for Nb 2 O 5 ) and of CdSe (2.45) are high compared to other optically transparent materials. Second, as molecular fragments of the Dion−Jacobsen phase KCa 2 Nb 3 O 10 , exfoliated Ca 2 Nb 3 O 10 sheets are atomically flat (see AFM scans in Figure S5).…”