Optical and Structural Properties of Spin Coated Cadmium Sulfide Thin Films

Thin films of cadmium sulfide have been synthesized using the spin coating technique. Films were fabricated on inexpensive amorphous glass substrates at spin speeds of 1500, 2200 and 2400 rpm for 30 seconds. Films were subsequently annealed at 200, 300 and 400 0C for one hour in air in order to crystallize the phase of CdS. Films were characterized using X-ray diffraction patterns (XRD) and UV-visible spectroscopy. According to XRD patterns, the phase of CdS was crystallized without any secondary phases. The particle size, dislocation density and strain were also estimated using XRD patterns. All the films indicate a strong orientation in (002) direction. The optical band gap was determined using UV absorption spectroscopy. Tauc model was employed to determine the optical band gap. According to our data, the optical band gap decreases with the particle size