Electrical, optical and morphological properties of chemically deposited nanostructured HgS-Bi2S3 composite thin films

(HgS)x(Bi2S3)1-x ternary composite semiconducting thin films have been successfully prepared by chemical bath deposition technique. The bath compositions include: mercuric chloride (HgCl2), bismuth nitrate (Bi(NO3)3.5H2O), sodium thiosulphate (Na2S2O3.5H2O), distilled water and ethylenediaminetetraacetic acid (EDTA), which served as a complexing agent. The colour of the deposits changed from whitish-brown to deep brown as the composition parameter x, was varied from 1 to 0. The films were characterized by X-ray diffraction (XRD), optical microscopy, optical absorption, and electrical resistivity measurement techniques. The dc electrical conductivities were measured in the temperature range 328-433 K. The resistivity and activation energy are found x dependent. The optical absorption measurements were carried out in the wavelength range 350-1100 nm to investigate dependence of bandgap energy of (HgS)x(Bi2S3)1-x on x.