Preparation and characterisation of effect Cr doping on nanostructured SnS thin films by CSP technique

Films of Undoped SnS and SnS:Cr have been prepared by using CSP method. From XRD patterns it is found that the prepared films are hexagonal wurtzite with a predominant peak (101) and the crystallite size is about (13. 28-15. 23) nm with Cr doping, whereas the strain decrease from 2. 58 to 2. 27 with Cr doping. AFM images show the Undoped SnS and SnS:Cr surface morphology. The average diameter was in the area of (82. 64), (67. 8) and (49. 75) nm for the (SnS, SnS:2% Cr and SnS:4% Cr) respectively. The surface roughness and rms values of the deposited films were (4. 78, 4. 18 and 1. 25) nm and (5. 83, 4. 06 and 2. 20) nm for SnS, SnS:2% Cr and SnS:4% Cr respectively. The transmittance of the film was observed to decrease for Cr doping, The decreasing in the optical energy gap which was found according to Tauc model were (1,48-1,37) eV, Results illustrate that both absorption coefficient and extinction coefficient of the films are increasing with increasing with Cr content in SnS thin films. The refractive index was found to decreased from 3,5-3,3 as the doping percentage increase.