Effect of Silver Dopant on Optical and Electrical Properties of Solution-Grown Cadmium Selenide Thin Films

In the present study, n-type thin films of CdSe have been grown onto glass substrates by using a solution growth technique. Different doping concentrations of Ag were doped in pure CdSe films, and the effects on the optoelectronic properties were observed. The optical band gaps (E_g) of these films were found to be dependent on doping concentration i.e., they decrease from 1.70± 0.02 eV to 1.50± 0.03 eV as doping concentration increases from 0.1 wt% to 25 wt%. Other optical parameters such as absorption coefficient, α, refractive index ‘n’ and dielectric constant ‘\varepsilon’ were also computed. The electrical conductivity of pure CdSe films was obtained as 10^-7 Ω^-1 cm^-1 while doped films have 10^-4 Ω^-1 cm^-1. Thermal activation energy of these films was estimated. Carrier concentration, mobility, thermoelectric power and photosensitivity were also studied at different dopant concentrations.