Influence of Zinc Doping on the Structural Optical and Gas Sensing in Tin Sulfide Nanostructured Thin Films

Nanostructured Zinc doped tin sulfide (we prepared thin films with 0, 1, and 3 wt% doping via spray pylysis technique which we successfully did. XRD analysis shows out that all the films are polycrystalline and have a preferred orientation along the (021). We saw that as Zn concentration increased so did the crystallinity which we proved by a 49% growth in crystallite size from 14.20 to 21.74 nm. Also we noted a drop in dislocation density and microstrain which in turn improved the crystalline quality and reduced lattice defects. AFM we used to see that we had a uniform distribution of spherical grains which we did, also we saw the average particle size reduce from 75.21 to 53.70 nm upon Zn doping which also we noted a reduction in surface roughness parameters for smoother film surfaces. We reported that the energy band gap reduced from 1.80 eV to 1.70 eV with increasing Zn concentration. At 120° C in our gas sensing study of NO2 we found that undoped SnS films did the best in terms of sensitivity which is what we did not see with the Zn doped films that we had which showed an increase in electrical resistance and a decreased sensitivity. We noted that the 3% Zn doped film had the highest resistance and the lowest gas response.