Copper-Content Dependent Structural and Electrical Properties of CZTS Films Formed by “Green” Colloidal Nanocrystals

Thin films of colloidal CZTS nanocrystals (NCs) synthesized using a “green” approach in water with variation the copper-to-tin ratio are investigated by Raman scattering, mid-infrared (molecular vibrations) and near-infrared (free carrier) absorption, X-ray photoemission spectroscopy (XPS), electrical conductivity, conductive atomic force microscopy (cAFM). We determined effect actual Cu content on phonon spectra, spectral parameters plasmon band. An increase conductivity NC upon annealing at 220 °C is explained three factors: formation CuxS nanophase surface, partial removal ligands, improved structural perfection. The presence phase concluded to be determinant factor for film conductivity. can reliably detected based analysis modified Auger parameter copper, derived from XPS data corroborated data. Partial ligand agreement core-level vibrational IR spectra. degree lattice perfection conveniently assessed as well. Further important information combination photoelectron optical work function, ionization potential, electron affinity films.