Effect of growth temperature and RF power on structural and optical properties of sputtered deposited PbS thin films

Abstract

Lead sulphide (PbS) nanocrystalline thin films have been grown from sputtering with the variation of growth temperature and RF-Power. The intensity of single dominant peak (200) in XRD-pattern increases by increasing the growth temperature from 175 ^oC to 200 ^oC and RF power from 80 W to 100 W, respectively. The crystallite size and the strain of as-deposited PbS thin films have been calculated from XRD-peak profile analysis. Microscopic surface and cross-section images show the improvement in thin films growth in terms of alignment of grains and thickness. The band gap of PbS thin films has been determined from UV-Vis absorption spectra, where the band gap decreases from 1.98 eV to 1.72 eV as the growth temperature and power increased from 175 °C and 80 W to 200 °C and 100 W.