The influence of the combined additive KMnO$_4$ and NH$_4$I on the photosensitive properties of PbS films

PbS, PbS(KMnO$_4$), PbS(NH$_4$I), PbS(KMnO$_4$, NH$_4$I) films with good adhesion to a glass substrate with a thickness of 250 to 490 nm were obtained by chemical deposition. Their composition, morphology, and photosensitive properties have been studied. Comprehensive studies using Raman, IR, and Auger spectroscopy established the presence on the surface of the films of a number of impurity oxygen-containing phases (PbO, PbCO$_3$, PbSO$_4$) and cyanamide PbCN$_2$. A synergistic effect of increasing the photoresponse of PbS films synthesized in the presence of a combination of KMnO$_4$ and NH$_4$I additives was revealed, which is due to the formation of an optically active phase of diiodine pentoxide I$_2$O$_5$ on the crystallite surface. Elemental analysis during layer-by-layer ion etching suggested the formation and incorporation of PbSO$_4$, PbCO$_3$, and PbCN$_2$ into the PbS(KMnO$_4$, NH$_4$I) film, and PbCN$_2$ into the PbS(KMnO$_4$) film.