Morphology, Structure, and Optical Properties of Nanocrystalline CdSe Films Doped with Copper

Abstract

Nanocrystalline CdSe films on a frosted glass substrate are synthesized via hydrochemical deposition with sodium selenosulfate using an additive of 5 × 10–4–10–3 mol/L copper(II) chloride. It is found that introducing copper(II) chloride into the reaction mixture accelerates the formation of solid phase CdSe and thins the cadmium selenide layer from 240 to 130–160 nm. It is established that doping with copper does not affect the cubic B3 structure (space group $$F\bar {4}3m$$ ) of the CdSe film, but 10−3 mol/L copper(II) chloride in the reactor reduces the period of the crystal lattice from 0.59967 to 0.59899 nm, due to the formation of supersaturated substitutional solid solution CuxCd1−xSe (x = 0.03). The band gap of the CdSe film, calculated according to light transmittance and diffuse reflectance, is 1.8 eV. Adding copper to the film lowers Еg to 1.6 eV. It is shown that doping with copper results in luminescence in the near-IR spectral range (680–780 nm) and changes conductivity from the n to the p type.