1：Experimental Design and Method Selection:

Pure and Ag doped CdS nanocrystalline thin ?lms were grown using analytical grade cadmium acetate and thiourea as cadmium and sulpher sources, respectively. The chemicals used in this study were purchased from Sigma Aldrich. First, 1 M cadmium acetate and 1 M thiourea solutions were prepared in 2-methoxyethanol and stirred separately for 1 h at room temperature. The prepared solutions were then mixed together at 1:1 volume ratio and were stirred for 10 min. The freshly prepared solution was used for ?lms casting using a spin coater onto ultrasonically cleaned glass substrates. Each ?lm was coated up to ten times at 3000 rpm for 30 s. After each coating, ?lms were heated at 100(cid:2)C to remove the residual solvents from the samples. Incorporation of silver atoms into the ?lms was performed using ion exchange with different molar concentrations of silver acetate solution. Silver acetate aqueous solutions with concentrations of

2：01 M, 02 M and 03 M were prepared. Then, CdS ?lms were immersed in these solutions for 20 s and annealed at 400(cid:

2)C to remove water and organic residuals from the ?lms. Film thicknesses were estimated using an Alpha Step system and were found to be in the range of (cid:3) 200 nm. In this work, thicknesses of all samples were found to be nearly the same. The thicknesses of samples are listed in Table I. In addition, the prepared samples were characterized using various techniques, as discussed in the next section.

3：Sample Selection and Data Sources:

The prepared samples were characterized using different techniques. A Shimadzu (X-600 Japan) x-ray diffractometer with Cu-Ka radiation at 35 kV and 30 mA was used to record x-ray diffraction spectra of the prepared ?lms. The scan was performed with step size of

4：02 ? /s for the angular range (cid:

3) 5? -70? and using powder x-ray diffraction analysis. Raman spectra of Ag doped nanocrystalline thin ?lms at 300 K were measured in the range of 150–1500 cm(cid:2)1, using a THERMO SCIENTIFIC, DXR FT-RAMAN spectrometer joined with a microscope with optical setting speci?cation at grating range (cid:3) 5–3500 cm(cid:2)1, laser power 2 mW and using a 532 nm ?lter. The estimated resolution was

5：1 to 3 cm(cid:

2)1 and the size of the aperture was ?xed at 50 lm. The surface morphological studies of the prepared ?lms were analyzed using a scanning electron microscope (JSM 6360 LA, Japan). AFM was also used to study the grain size and roughness of the prepared samples using an NT-MDT atomic force microscope in non-contact mode. The transmittance, absorbance and re?ectance spectra of the ?lms in the range 200 nm to 2500 nm were recorded using a UV-Vis-Nir spectrophotometer (JASCO V-570).