Thin films of Tin Iodide (Snl2), Manganese Bromide (MnBr2), Lead bromide (PbBr2), Lead Iodide (Pbl2) Lead Sulphide (PbS) and Silver Sulphide (Ag2S) were grown on glass slides using the Chemical Bath Deposition (CBD) method also called the Solution Growth Technique (SGT) [2, 9, 10]. The surface structures of the films were obtained by taking photomicrographs of the films with a Leitz Labourlux Photomicroscope. The photomicrographs were then used to study the surface microstructure of the films by applying the Jeffries (Planetric) measurements with a circle 79.8mm in diameter drawn on a transparency. This drawn circle was placed on each photomicrograph one after the other to count the number of grains falling within the circle N1 and those intersecting the circle N2. The values of N1 and N2 were then used to compute the grain size parameters by applying equations 6 to 15, while the porosity factors were obtained with equations 16 and 17. Only films whose thickness is such that the individual grains are visible and identifiable on the photomicrographs were used for this study [2, 4].

After taking the photomicrographs of the films the coated slides were then put in the transmission beam path of a Pye-Unicam (Sp 1000) spectrophotometer to obtain the spectral transmittance curves of the films, with a similar but blank glass slide in the reference beam path of the spectrophotometer.

Plates 1 = 6 show the photomicrographs of the films mentioned above respectively, while table 1 shows the computed grain size parameters and porosity factors for the films. Figs 1 — 3 shows the spectral transmittance curves of the films.

2. Structure — Spectral Relationship