Investigation of the Physical Properties of Indium Sulfide Thin Films Grown by Chemical Bath Deposition Method

Indium sulfide thin films were synthesized on microscope glass substrates at room temperature for 55 h, and at 70 degrees C for 6 h and 4 h by using chemical bath deposition technique. The obtained films were characterized by scanning electron microscope, atomic force microscope, energy dispersive X-ray spectroscopy, X-ray diffraction and UV-vis spectroscopy. X-ray diffraction results showed that all films had amorphous structure. From the atomic force microscope micrographs, the average grain size of the deposited films increased from 20 nm to 100 nm with increasing film thickness from 551 nm to 798 the surface roughness varied in the same manner from approximately 5.10 nm to 33 nm. Energy dispersive X-ray spectroscopy results indicated that the average atomic ratio of S/In in the films ranged from 0.93 to 1.21. The direct band gap of the films decreased from 3.80 eV to 3.57 eV with increasing both grain size and film thickness. Moreover, optical constants such as refractive index, extinction coefficient, real and imaginary parts of dielectric constant were calculated. Refractive index value of the films increased from 2.06 to 3.75 with an increment in both grain size and film thickness. The effect of film thickness on the deposited films were determined.